The philosophical culture called falsafa began as a project of recovery. Beginning under the early Abbasid caliphs, and reaching its height under al-Mamun in the ninth century, patrons in Baghdad funded scholars, many of them Christian and Sabian as well as Muslim, to render the surviving corpus of Greek philosophy and science into Arabic. Aristotle arrived first, together with the Neoplatonic commentaries that had shaped how late antiquity itself read him, so that the Aristotle the falasifa inherited already carried Plotinus and Proclus folded into his text.
Al-Kindi, often called the first Arab philosopher, argued that this imported wisdom was compatible with revelation rather than a rival to it. Al-Farabi then built the systematic apparatus, logic, political philosophy and a metaphysics of the First Cause, that earned him the title of Second Teacher. Avicenna's Book of Healing became the reference work against which every later philosopher in the tradition, Muslim, Christian and Jewish alike, measured his own thought.
The tradition did not end at the eastern edge of the Islamic world. In Cordoba, Averroes wrote his long commentaries on Aristotle specifically to recover the philosopher from what he judged Avicenna's Neoplatonic distortions, and those commentaries, translated into Latin and Hebrew, gave medieval Paris its Averroism and gave Maimonides the philosophical vocabulary of the Guide of the Perplexed. Falsafa's afterlife outlasted the civilization that produced it, carried forward by readers who did not share its language or its faith.