PAUL FREEDMAN: OK, in 743,
civil war started within the
Umayyad my family over
the caliphal succession.
This war broke out in Persia,
which is a little unusual
because until this point the
subversive, discontented,
proto-Shiite region had been
what is called Kufa, basically
southern Iraq as it now is.
It's thought that this revolt
against the Umayyads had the
support of the mawali.
And it makes sense that if it
was in Persia, the largest
non-Arab Muslim country, it
makes sense that you would
have the most concentration of
non-Arab Muslims, that is to
say converts or the descendants
of converts, who
might feel that the egalitarian
promises of Islam
had been betrayed and that in
fact the religion was an Arab
one in which non-Arabs were
in a subordinate position.
The non-Arab Muslims of Persia
had converted, some from
Christianity, most from
Zoroastrianism, a religion of
central Asia.
Wickham takes issue with this.
If you go back to your reading,
pages 292-294, he
says that he doesn't think
that the discontent was
related to somehow the Umayyads,
being an excessively
Arab, rather than Muslim,
dynasty or that they provoked
discontent among recent
converts.
So this is an open question.
I think there's got to be some
Mawali discontent, but as
we've seen already there's
plenty of discontent;
Shiite-Sunni being the most
obvious, inter-tribal,
regional, problems of holding
this empire together.
At any rate, in 749-750, the
Umayyad caliph was deposed by
a member of another family
known as the Abbasids.
This new caliph, Abu'l Abbas,
Abbas- the Abbasids.
The Abbasids were early
followers of Muhammad,
although not particularly
heroic ones.
The family had been supporters,
but hadn't taken
very many risks.
So the Abbasids are
not heroes, though
they are an old family.
The Abbasids came to power with
support from the Shiites.
This is what Wickham means
by what he calls their
"salvationist theology";
salvationist meaning that they
were going to restore the
religious fervor that the
Umayyads had dissipated.
So that they were originally
supposed to represent a
return, a reformation, of Islam
to its austere roots in
which the caliph was a modest,
clean-living, austere figure.
They very quickly, if that was
the hope of the Shiites, the
Abbasids very, very quickly
betrayed this.
They moved their capital from
Damascus, the Umayyad capital,
to a new city that
they constructed
in the desert, Baghdad.
A city built in concentric
circles as a planned round
fortress city, but also a
commercial city and, of
course, predominately city
of administration.
It was located thirty miles from
the old Persian capital.
The Persian Empire was
ruled from Ctesiphon.
Relocating the capital of the
caliphate to Baghdad has a
number of obvious
implications.
While most historians would not
be quite as confident as
Peter Brown, whom you're reading
for Wednesday is, that
this represents the
Persianization of the
caliphate, it is certainly true
that moving the capital
to modern Iraq, to the
Mesopotamian part of the
former Persian Empire, orients
the caliphate further to the
East. It changes the center of
gravity of the caliphate from
the Mediterranean, as in
Damascus, basically to Persia,
India, the lands between them,
modern Afghanistan, Pakistan.
At least those are as important,
if not more so now,
than the Mediterranean.
Even though the empire stretches
from the Indus River
to the Atlantic, its center of
gravity has clearly shifted
This has implications also for
culture, as we'll talk about
in a moment.
The accomplishment of the
Abbasid caliphate in terms of
culture is to bring together
realms that had not been in
very much contact with each
other, certainly not in terms
of ideas, namely India, Persia,
and the Roman Empire,
the former empire of the
Mediterranean East. Persia
stands in the middle between
India and the West. To the
extent that Persia is not an
isolated empire of its own but
a crossroads, this means that
there's all this exchange of
information, techniques,
science, art, and culture.
But most of all, the
establishment of Baghdad
clearly means a different
kind of rulership.
One that it does not break with
the Umayyads, but rather,
to some extent, elaborates
on it.
This is an empire.
It is not a kind of
sacred kingdom of
people living in tents.
This is an empire more open
to Eastern influences.
That is to say somewhat more
Persian in its style.
Less Mediterranean and
originally more Shi'ite.
So the significance of the
Abbasid takeover is really
basically twofold.
One is this move east to Baghdad
with all that it
symbolizes that I just got
through saying, the influence
of non-Arab Muslims, and the
creation of a complex
administration, an even more
complex administration than
that of the Umayyads.
And then, two, it shows the
influence of the Shi'ites.
This begins as a Shi'ite
victory, but very quickly the
Shiites, as I said, are
disillusioned, and so it also
shows the limitations
of the Shi'ites.
The Shi'ites don't just want a
non-Arab dominated Islamic
world, they want what we called
last week a "republican
administration", a
non-monarchical polity.
And the Abbasids are
monarchical if they're anything.
Until the early tenth century,
when the Abbasid caliphate
starts to break up, the world
of Islam was splendid, rich,
cultivated, and scientifically
progressive.
There would be no more great
conquests, particularly in the
West. Already, before the
Abbasids took power, we've
pointed to two moments in which
the Arab expansion, or
the Islamic expansion,
was stopped.
One in 717 before the walls of
Constantinople, in the failed
Siege of Constantinople.
Two, the battle of Poitiers,
not that far from Paris in
northern France, in 733.
A battle at which the
Merovingians, or really their
high servants, the so-called
Mayors of the Palace, defeated
Arab raiders who then retreated
basically back to Spain.
To some extent these defeats in
the West were not so much
defeats from the caliph's
point of view as a
reorientation.
In 750 moving the capital to
Baghdad from Damascus also
means less interest in the West;
less interest in trying
to take over France, if that was
ever a serious goal; less
interest in the besieging
Constantinople.
The Abbasids begin by inviting
all of the Umayyad survivors
to a banquet supposed to be a
banquet of reconciliation.
And instead they had their
servitors kill all of the
Umayyads at the dinner table,
spread a leather cloth over
them-- some of them were already
dead, some of them
merely wounded--
and with the leather cloth over
them set the table again
and banqueted on their dead
and dying enemies.
Satisfying, definitely.
One Umayyad escaped.
Not from the banquet, but
he had the foresight
to say he was busy.
And he escaped as far as he
could go in the Muslim world,
namely Spain.
The last Umayyad, then, Abd
al-Rahman, came to Spain and
was acclaimed by the population,
or got himself to
be acclaimed by the population,
and ruled in Spain
as the first Islamic ruler
to defy the caliphate.
Thus the first independent
Islamic kingdom, we can call
it-- although they don't
use that term--
the first independent Islamic
kingdom, independent of the
caliphate, would be Spain.
The Umayyad ruler actually
recognized Baghdad.
He did not proclaim himself
a rival caliph.
It was easy for him to recognize
Baghdad 3,000 miles
away, or whatever it is,
they weren't going to
come and get him.
He took the title of emir, a
ruler who is more like a title
of a governor than
that of a king.
Nevertheless, as I said, Islamic
Spain represents the
first piece of the caliphal
empire to break off.
When the Abbasid caliphate ran
into trouble in the early 10th
century, then the Umayyad ruler
of Spain proclaimed
himself caliph.
In 929 he proclaimed himself
caliph of Cordoba.
Cordoba was the capital
of Umayyad Spain.
So at this point Spain becomes
the most splendid, most
cultivated part of the
Islamic world.
So if the period of the maximum
power and splendor of
the Abbasid caliphate was
roughly 750-910, the period of
maximum splendor of the
caliphate of Cordoba in
Al-Andalus, or Spain, was
about 850 to its sudden
collapse in 1009.
Questions?
Problems?
Lot of names here.
We don't have a final exam,
so what do you care?
But I realize it is a dramatic
story, but one with a large
cast of characters.
By now you're used to
this in history.
Whether these are good cat names
or not, I'm not as sure
as I am with the barbarians,
but worth experiments.
As Wickham has described, the
Abbasid caliphate was based on
tax collection and
administration.
And your response to that may
be, "Yeah, well so what?" But
that's not true of
all the states
that we've been studying.
If you take something like
Merovingian Gaul, even though
in the early period they're
still collecting taxes--
remember Fredegund tells
Chilperic, "Let's burn these
tax records and maybe our
sons will be cured of
their disease by God."--
but you'll have scene in
Gregory of Tours, that
basically the Merovingians are
rich because of plunder,
military expeditions,
and land.
Land, above all, is the source
of wealth in the kingdoms of
Western Europe.
Land, and the peasants
to till it.
Obviously it's no good if
it's just empty land.
Usually not, at least. It's
productive land, and this is
the source of wealth.
Therefore the state gains its
wealth on the basis of things
like land, military power, and
not on the basis of taxing an
economy that is more sluggish,
has less trade, less income
than in the cities of
the Muslim world.
The caliphate was a tax-paying
state with a central army.
Therefore the nobility, as
such as it was, was not a
group of local potentates, as
they had been under the late
Roman Empire, great landowners
for example.
Nor was it a military elite
quasi-independent, whose
loyalty to the ruler was
conditional on their own
interests, as we've seen with
the Merovingian knights.
Rather, it was a complicated
administration, served as a
structure of a vast empire, and
the tax revenue came into
the caliph, whose
administration, whose civilian
administration, was supreme over
army, over local elites,
over great landowners,
at least for a time.
The Abbasid Empire was the
greatest state in the
world at that time.
Its only rival might have been
T'ang, China, but this is the
period of the decline
of that empire.
Baghdad was the wealthiest and
largest city in the world.
Among the programs of the
Abbasids, in addition to
building this planned city,
creating a certain kind of
military structure,
consolidating their conquests,
among their plans was
a cultural program.
The cultural flowering of the
Abbasid caliphate is, in part,
a planned flowering.
Not just a spontaneous one.
The caliphs funded translations
into Arabic of
Greek and Persian texts
dealing with science,
geography, mathematics,
philosophy, and medicine, in
particular.
In 830, one of the caliphs
established in Baghdad a kind
of combination of library and
research institute, called the
House of Wisdom.
The House of Wisdom, in the
first place, paid for and
sponsored translations, but
it also conducted research
activities.
Things like an effort
to measure the
circumference of the earth.
The kind of thing that--
you know, how do you actually
do that without modern
instrumentation?
A lot of the material that they
translated was from Greek
scientific works.
Where did they get these?
In some cases, they got them
from Byzantium, from
Constantinople itself.
It's said that one treaty
between Constantinople and
Baghdad called for, among other
things, the Byzantine
emperor to lend to Baghdad a
copy of Ptolemy's geography.
Ptolemy, one of the great
geographers of the ancient
world, author of a book called
The Great Geography, known in
the West later on when it was
translated into Latin from the
Arabic as the Almagest, which is
a Latin garbling of an Arab
garbling of the original Greek
title of the work.
So this was known in the West,
even when it was translated
into Latin, as the Almagest.
And it was just one of many
works that, when they finally
reached Western Europe in
translations from the Arabic,
kept a kind of version of
their Arabic name.
But the idea that, as part of
a treaty, one of the things
was you lend us this copy of
Ptolemy so that we can
translate it into Arabic, shows
the commitment of the
rulers to the expansion of
practical knowledge.
What Islamic scholars,
scientists, and policy makers
were most interested in from the
classical world, that is
from the world of the
Greek and Roman
civilization, was science.
Broadly speaking, science.
They were less concerned with
Greek plays, Greek poetry,
Greek literature in general.
This is partly because they
had their own poetic
tradition, in Arabic, and partly
because their real
source of inspiration for
literature would be Persia.
The stories, as in the Arabian
Nights, and the kind of
lyrical poetry of the Arabs,
like love poetry, or sensuous
poetry, is either home-grown
or Persian.
So they translated things like
Euclid on geometry, or the
physician Dioscorides, who
wrote, not the only, but the
leading pharmaceutical manual.
Pharmaceutical manual, a list
of drugs, their properties,
what they come from,
what they can cure.
However, although they
concentrated on science, they
also were interested
in philosophy.
They were also interested in
propositions, the nature of
reality, metaphysics, and the
major project in this realm
was the translation
of Aristotle.
Aristotle is someone who wrote
on everything: on drama,
poetry, politics, metaphysics,
ethics, animals, physics.
And so his influence would be
tremendous in all three
religions that we are concerned
with: Islam,
Christianity, and Judaism.
His influence tends
to be in two
related realms, or factors.
One is its comprehensiveness.
They didn't translate everything
of Aristotle's, but
all three civilizations were
aware of Aristotle as a
universal thinker.
That somewhere, in the work of
Aristotle, there's something
about everything that's
worth studying.
He is then, an encyclopedic
thinker in a way
that Plato is not.
Plato is not interested
in the natural world.
If you go to Plato for
information about animals, or
plants, you're going to be out
of luck because Plato despises
things like that.
Plato is very interested in
ethics, in how to live life,
in reality, in the relationship
between matter
and spirit, but he's not
a scientist. He--
to put it mildly--
he's not interested in the
material world, whereas
Aristotle believes that the
material world, although not
necessarily the be-all
and end-all of
everything, is reliable.
That our senses can give us
decent information, that
observation of the natural
world leads to more than
merely practical knowledge of,
say, how to plow, or how to
plan things, but leads to
knowledge of what creation,
what nature, is.
So Aristotle is encyclopedic
and he's also rational.
This is the second contribution
that Aristotle makes.
Rationality, that anything from
plays to rocks can be
understood in terms of
logical analysis.
This is fine when it comes to
plays and rocks, but what
about metaphysics?
What about the world
of religion?
Aristotle has a profound
influence here, again not only
on Islam, but on Judaism and
Christianity, because he
essentially encourages a
rational view of God.
Now Aristotle is himself not
much of a theist, that is to
say, Aristotle doesn't go on
about God very much, and
whatever God there is in
Aristotle is not a personal
god to whom you would pray on
the assumption, or in the
belief, that he was interested
in your well-being.
The closest Aristotle gets to
God is the notion of a kind of
Great Mechanic.
The Prime Mover, as he would
be called in Western
philosophy.
The guy who makes the mechanism,
sets it going, and
maybe, every so often
maintains it.
Maybe.
A little oil here, a little bit
of timing there, but he's
not the God of Gregory
of Tours.
He's not the God who is
inspiring saints to get
revenge when their powers are
questioned, or when somebody
steals hay from them.
This is not Aristotle's god.
Aristotle's god is not concerned
with our little
petty squabbles.
It's not Muhammad's God
exactly, either.
It's not a god who brings a
victory in battle, who's
interested in a new prophecy
that will seal all the
previous prophets, it's a
somewhat mechanistic god.
It's an eighteenth-century god,
even a sort of deist god,
for those of you who
have studied that.
The notion that the world must
have been created by God,
because it has a lot
of design in it.
It works.
One animal gives birth to
another animal just like it,
the tides go in and out, the
weather is usually rational:
winter is usually cold,
Halloween is usually crisp.
That's imposed by some kind
of original order.
Just like if you went and found
a watch on a deserted
pathway, you wouldn't assume
that nature had constructed
the watch, that it just was
growing there the way the
ferns were growing
by the path.
You would assume some artificer
had made it.
But that doesn't mean that the
artificer is still alive,
still interested in the watch,
inclined to take care of you.
I go on this detour, or
seeming detour about
Aristotle, because he's
important to everything in the
period that we're discussing,
and also in the period that is
concerned for the West in the
continuation of this course in
History 211.
There are three thinkers, just
to take examples, the most
famous thinkers in each of the
Jewish, Christian, and Islamic
traditions, who embrace
Aristotle and in doing so
embrace the idea of god as a
rational companion to man.
These are the Arab philosopher,
known in the West
as Averroes.
Here again, as with Almagest,
we're using his sort of
Latin-garbled name.
Averroes, active in
Spain, 1126-1198.
Maimonides, perhaps the greatest
Jewish philosopher.
A rabbi, a physician, a
courtier, and a philosopher,
also active in Spain, but
also in Egypt 1135-1204.
And Thomas Aquinas, who spent
most of his career teaching at
the University of Paris,
1225-1274.
All of these thinkers
embraced Aristotle.
The Latin ones, like
Aquinas, via
translations from the Arabic.
Aristotle was known in the
medieval West, not from the
Greek originals, but from
translations made from Arabic
into Latin.
All believe that reason and
faith are compatible.
All based their outlook, not
only on nature, but on God, on
an Aristotelian form
of knowledge.
Interesting, in that Aristotle
knew nothing about Judaism,
Christianity, or Islam.
So, what is it about Aristotle,
what is it about
Diascordes, what is it about
Ptolemy, of all of these
scientists and philosophers that
is of such fascination to
the Islamic world?
All of this emphasis that we've
made on Islamic culture
and its openness to other
influences may seem strange to
you in light of the reputation
Islam has in modern America,
or at least in many circles of
modern America and Europe, as
being obscurantist, or
anti-modern, or religiously
inflexible.
I teach a group of retired
people where I live, just
outside New York, and we're
studying Islamic Spain.
And they are astounded at what
I've just described, at the
openness of Islam to other
civilizations, at its
tolerance, at its
curiosity about
classical and Persian science.
And I was surprised because this
is not new information.
This is not something that
historians have just come up
with and just discovered.
If you read medieval history
textbooks of a hundred years
ago, it's in there.
Everybody knows that Aristotle
was translated from Arabic
into Latin.
"Everybody knows", everybody
who studied
the Middle Ages knows.
And I said to them, because you
can't say to older people,
"Oh, well you know your
education is actually not very
good," the way we say
to you all the time.
Or, "Your attention span is
not very good, because all
you're doing is you're plugged
in to your social world".
No, these people went to college
in the tough old days,
allegedly, and they're like,
"God, I thought Islam was just
this sort of frozen religion
that had never changed." So
you don't have that
disadvantage.
You don't have that idea, and
so I'm not going to browbeat
you with it on the basis of
the experience of teaching
seventy-year-olds.
But there it is.
I do not accept the notion, well
with one exception, with
of one honorable exception--
STUDENT: I'm forty-nine.
PROFESSOR: Right, me too.
I don't want to go into a long
discussion about, "Islam,
right or wrong?" Or, "Islam,
progressive or regressive?" I
will say this: there are those
who believe, wrongly in my
opinion, that there's always
been this "clash of
civilization", as it's sometimes
called, between the
progressive Christian West and
the obscurantist Islamic East.
I don't accept that, in part for
reasons you've just heard.
There is no consistent Islamic
tradition of the maintenance
of dogma, or the conversion
of the world by force.
Insofar as that exists now, it
is, in my opinion, a modern
phenomenon.
It is a phenomenon that results
from an encounter with
the West beginning around the
time of Napoleon's conquest of
Egypt, perhaps.
It's about two centuries old.
There's another kind of
belief that at some
point things changed.
There's a book by Bernard
Lewis, the most eminent
Western scholar of
Islamic culture,
called "What Went Wrong".
And so Lewis' assumption is
that the world that I'm
describing, the Abbasid
caliphate, is an open society
and at some point and for some
reasons, the Islamic world
closed itself.
It became less susceptible to
outside influence, more
suspicious of it, more dogmatic,
more anti-modern,
more fixated on literalism, what
in the Western Christian
tradition would be called
fundamentalism, and on
tradition.
I don't really like this either,
because it sees all
progress as the property of
Western civilization.
And it's not that I am not
interested in Western
civilization.
I've taught it.
I've taught it because
I liked it.
I'm not somebody who believes
that it's all a tale of
oppression, but I don't think
that anybody who diverts from
the path of Western civilization
at some point is
going off the cliff, or off the
trail, and into the woods.
There are a lot of different
civilizations out there.
There's a third related idea
that the Arabs are just
intermediaries.
Yeah, it's great, they translate
Aristotle so that
the real guys who can really use
Aristotle, Thomas Aquinas
et al, can get started.
I don't accept that, either,
because they
do more than that.
They do an awful lot of original
research in medicine,
in mathematics, in philosophy.
But, within all of this, to my
mind, fruitless speculation,
there is a kernel of what is
an interesting problem.
And the interesting problem is,
why were the Arabs so much
more successful in assimilating
conquered
cultures than other
invaders were?
Say, for example, the Germans.
You don't get this kind of
efflorescence of culture under
the barbarian occupants of
the former Roman Empire.
We're talking, not just about
cultural survival, keep in
mind, but about an expansion
of science and allied arts.
I'd say there are maybe four
factors that encouraged the
Arab conquest to absorb
these new influences.
They're not in themselves
explanations, but they are
certainly background factors.
The fact that the conquest was
quick and relatively painless,
and that it was not really
a religious war.
Two, and I think here
very important, the
elimination of frontiers.
I mentioned this
briefly before.
You get Persian as well
as Greek astronomy.
From India you get things like
chess, so called Arabic
numerals, which actually, as we
all know, come from India.
These things come into the Arab
and Persian worlds from
India and eventually to Europe
as well, in a world in which
there are no frontiers between
India and North Africa.
They could go these thousands
of miles peacefully.
The elimination of linguistic
boundaries.
Arabic becomes the language of
learning, as much as Latin
would be in the European Middle
Ages, much as English
has tended to become
in our era.
So Maimonides, the great Jewish
philosopher, wrote
largely in Arabic.
The Christians of Spain, so
called Mozarabic Christians,
studied Arabic, fought in
Arabic, wrote in Arabic.
And finally, number four, the
attitude of the conquerors and
the conquered.
The attitude of the conquerors
was what Peter Brown in the
reading for Wednesday will call,
"a garden protected by
our spears".
This is a quote from one
of the conquerors.
The Arab conquerors considered
these to be wonderful
civilizations that they were
not going to pillage or
destroy, but rather protect.
"A garden protected by our
spears." But they were planning
on enjoying the
garden, not merely standing on
the outside defending it for
other people to enjoy.
The conquerors were confident
in their religion, so
confident that they didn't need
for others to recognize
it or convert.
It also gave them the confidence
to accept new ideas
from Greek civilization,
from Persian
civilization, from India.
But there's also the attitude
of the conquered.
Brown says that, "as the storm
of the Arab armies rolled over
the horizon, the population of
the Near East sat back to
enjoy the sunshine." The
Islamic conquest was of
benefit, and perceived as of
benefit, by most of the people
who were conquered.
A kind of counter example,
in a way, explains this.
In Cordoba, the capital of
the Umayyad caliphate, or
soon-to-be caliphate of Spain,
a group of Christians around
850, were so upset at the
contented attitude of the
Christians of Islamic Spain--
who were, if not a majority,
probably about fifty percent,
close to fifty percent
at this time--
these more fanatical, or at
least more serious Christians,
were so angry that all of their
compatriots seemed to be
just fine with Islamic rule
that they got up in the
marketplace of Cordoba and
denounced Muhammad as a
charlatan, as a false god,
and as not a prophet.
And while Islam is tolerant,
that is something that you
couldn't do.
So they did the thing that was
most defiant of the regime,
really the moral equivalent
of burning yourself in the
marketplace, and indeed they
were imprisoned, told to
recant, and when they didn't
recant, they were executed.
There are about fifty of these
"Martyrs of Cordoba", as
they're called.
But they have to seek martyrdom
because they have to
look for it, they have to create
it, because almost all
the rest of their compatriots
are perfectly happy to be
Mozarabic Christians, practicing
the freedom of
their religion under a
beneficent regime.
Beneficent in the eyes of these
Martyr Christians, but
nevertheless the regime
of the devil.
This shows you something about
the nature of the Arab
conquest and occupation.
Let me just speak briefly about
a couple of aspects of
what the Islamic world was
interested in studying, and we
may continue over into next time
since the lecture on the
seventh century is actually
rather short.
Let's start with mathematics.
The great accomplishment of this
time is the introduction
of Arabic numbers, which if
you've ever tried to multiply
or divide with Roman numerals,
are superior.
Arabic numbers come from India,
and along with this
system of numerals, they
imported zero--
both the number, or the
non-number, and the concept.
The concept of zero allows for
things like decimal places,
which are also developed
at this time.
From India the Arabs get the
kind of very basic ideas of
trigonometry, the
sine function.
But it is their own researches,
their own
progress, that leads to the
discovery, or development, of
the five other functions.
And here I'm on kind of tricky
ground, because despite what
they tell you about math
literacy and how important it
is, I haven't used this
since tenth grade.
But I do remember the cosine,
the tangent, the cotangent,
the secant, and the
cosecant, right?
All of these are discovered
by the Arabs.
They built on an edifice who's
foundation is Indian
mathematics.
In the early ninth century, a
scholar attached to that House
of Wisdom in Baghdad, named
Al-Khuarizm, in the early
ninth century, Al-Khuarizmi
writes a book with the title
that can be translated as
something like, The Book of
Addition and Subtraction
According to the Hindu
Calculation.
And this is what incorporates
zero and decimal places, and
interestingly enough this book
is known only from its
translation into Latin.
The Latin version survives,
whereas the
original Arabic does not.
Within a century of the
publication of this book,
decimal fractions have been
developed, square roots, the
value of pi to sixteen decimal
places had been calculated.
Al-Khuarizm is also the author
of a treatise on algebra.
The word "algebra" comes from
al-jabr, which is sort of
restoring, restoring something
that has been imbalanced and
that you're now going about to
balance, which of course is,
in a way, the visual
nature of algebra.
Al-Khuarizmi was also
an astronomer.
He developed star tables that
allowed one to locate the
planets and stars at different
times of year and
at different latitudes.
This is what allows the making
of things like astrolabes or,
later, sextants.
These are things that describe
the sky at a particular
[correction: place]--
that allow you then to keep
time; and also to navigate; to
calculate time for things
like prayers, or feasts,
celebrations; also to
cast horoscopes.
I'll work a little more with
you on geography, medicine,
and then summarize the Abbasids
at the beginning of
our next class.
So I'll let you go for now.
Thanks.
