Carried Across · Chapter 5
For love of the Almagest
When Gerard of Cremona died in Toledo in 1187, his students were afraid his name would disappear. He had never signed his translations. So they appended to one of his manuscripts a short memorial: a vita, a eulogy, and a list of everything he had translated from Arabic into Latin. The list runs past seventy works. It includes Euclid's Elements, al-Khwarizmi's algebra, Avicenna's Canon of Medicine, item 63, and the book that started it all.
The vita explains how the whole thing happened, and its explanation is a love story. Gerard, it says, educated in the schools of Italy, went to Toledo for love of the Almagest, Ptolemy's great mathematical model of the heavens, which he could not find at all among the Latins. He arrived in a city that had been Castilian for two generations but Arabic in its libraries, saw the abundance of books in Arabic on every subject, and, regretting the poverty of the Latins in these things, he learned the Arabic language in order to translate. He stayed for the rest of his life, to the end of his days, as the students put it, transmitting to the Latin world, as if to a beloved heir, the books he judged finest, as plainly and intelligibly as he could.
Strip the hagiography and the residue is still astonishing. A grown professional emigrated permanently, acquired a difficult language, and spent four decades producing translations at a rate that implies near-daily work, all traceable to the want of one book. The seventy-item list is what an obsession looks like after compound interest.
This chapter is a correction to the last one. The economics of demand explains the translation movement; it does not explain the translators. No commissioning class summoned Gerard. The twelfth century's wave of Arabic-to-Latin translation was, to a degree that embarrasses structural explanation, the work of a few dozen individuals who wanted, personally and unreasonably, to know what was in the books.
But the obsessives were not distributed at random. They converged on one city, and the reason is a date: 1085, when Alfonso VI of Castile took Toledo. The city changed sovereigns without a sack, and that detail moved history, because its libraries, the accumulated book wealth of al-Andalus, passed intact into a Christian kingdom. For the scholars of Latin Europe, who had been hearing for a century that the Saracens held sciences the Latins lacked, Toledo after 1085 was an open vault. They came the way prospectors come. Gerard from Italy. Robert from England, by way of Spain's northeast. Daniel of Morley, who tells us he passed over Paris, found its learning threadbare, and went where the Arabs' teaching held the field. The vault, plus the prospectors, plus resident communities of Mozarabs and Jews who lived in both languages: that compound, and not any prince's program, was the Toledan translation movement.
The work itself was nothing like the lone-scholar image the word "translator" suggests. Daniel of Morley heard Gerard dispute before a public audience in Toledo, on the influence of the stars no less, and in telling the story identifies him, almost in passing, as the man "who Latinized the Almagest with Galib the Mozarab interpreting." That subordinate clause is our window onto the standard Toledan method: a relay performed aloud, the Arabic read and rendered into Romance vernacular by a local Christian raised in the language, the Romance recast into Latin by the visitor. Some of the most consequential books in European history passed through an intermediate stage that was never written down at all, a spoken Castilian that lived for seconds between two other languages. The lone genius was actually a duet, and the half of it whose language died in the air mostly lost its name. The students' list preserves Gerard. Almost nothing preserves Galib.
What drove the visitors is best read off what they did when no one was assigning topics. Adelard of Bath, the Englishman of the generation before Gerard, wandered the Norman Mediterranean for seven years and came home preaching what he had learned, framing reason against the authority of the schools; he translated Euclid from the Arabic around 1120 and al-Khwarizmi's astronomical tables in 1126, the first of their kind in Latin. Nobody in England was buying zijes in 1126. There was no demand to speak of; Adelard was supplying anyway, on conviction that this was where knowledge lived. The demand arrived a generation later, when the universities began to form around precisely the corpus the obsessives had stockpiled. The prospectors had, in effect, front-run the European mind.
One colophon from this world deserves a close look, because it preserves both the precision and the strangeness of the moment. In 1145, at Segovia, an Englishman known as Robert of Chester finished the first Latin translation of al-Khwarizmi's algebra, the book whose title gave the discipline its name. His colophon dates the work to "era 1183."
Era 1183? Spain reckoned years by the Spanish era, which runs thirty-eight years ahead of Anno Domini, a local calendar for a local world. The famous date 1145, the year algebra entered Latin, is itself a conversion, performed by historians on a number Robert wrote for Iberian readers. The detail is small and perfect: even the timestamp on the act of translation needed translating.
And Robert opens a genuinely tantalizing question of identity. An Englishman called Robert of Ketton, working in the Ebro valley in these exact years, produced in 1143, for Peter the Venerable of Cluny, the first Latin translation of the Quran. Whether Ketton and Chester are one man or two has been argued for a century and is still open; the documents allow either. If they are one, then a single Englishman, in the space of three years, carried into Latin both the scripture of Islam and the algebra of Baghdad, polemic and mathematics from the same pen, paid for by an abbot in one case and by curiosity in the other. If they are two, the coincidence is nearly as instructive: the Arabic-to-Latin frontier of the 1140s was so narrow that it could barely keep two Roberts distinct.
Either way, the frontier ran on individuals. And individual attribution has individual failure modes, which the atlas behind this book grades honestly. Adelard's 1126 tables are "presumably" his: manuscripts interleave the work of a collaborator or precursor, Petrus Alfonsi, and one version of the tables is keyed to 1116. Of the fifty-plus manuscripts of Michael Scot's Averroes, only a few name him; the attribution of the rest stands on style. Gerard's own list was compiled after his death, by students with a motive to be generous. None of this is scandal. It is what records look like when an enterprise of civilizational scale is conducted by private persons, without institutions to stamp the paperwork. The age of the obsessives bequeathed Europe a library and a paperwork problem, and the paperwork problem is the price of the fact that no one was in charge.
That fact deserves dwelling on, because nothing in this chapter or the last was directed by anyone. A captured library here, a hungry court there, bilingual communities in the middle, and a scattering of individuals with fixations: out of those parts, with no architect, the connected system assembled itself. Before we examine that assembly, though, honesty requires a chapter on what the system did to the books in its care. Carriers are not couriers. They change what they carry, and some of the changes ran deep.