In the tenth century (using the Roman calendar) the library of Cordoba was a wonder of the world, with more than half a million handwritten volumes on every subject under the sun, with the index alone stretching to more than forty volumes. The life’s work of Caliph al-Hakam II, the library drew together books from the breadth of the Mediterranean, both temporally and geographically; in addition to contemporary works, the caliph commissioned a massive translation effort that compiled hundreds of works in ancient Latin and Greek into Arabic, a wealth of knowledge and learning that court visitors called the golden center of the West at a time when the largest Christian library had a collection numbering in the dozens.
Almost all of it was burned following his death.
Burned not through conquest or arson or accident, but piecemeal over decades by less studious usurpers bargaining with the ulama for power. Temporal power bartered from ecclesiastical, with al-Hakam’s son living a sterile, silent life in the shadow of al-Mansur the Victorious; the college of the faithful demanded a purer devotion from al-Mansur, and to prove his bonafides onto the bonfire most of the books went.
Still it was a golden age; al-Mansur’s bargain worked. Cordoba thrived, the silent outrage of later eras inaudible and unregarded.