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The source library.

Explore early cities, languages, religion, Kabbalah, alchemy, philosophy, human origins, and disputed history. Open a guide, follow its sources, and keep the next question in view.

This collection contains published introductions to the growing knowledge base. Each guide links its sources; traditions and open hypotheses retain their context.

1 of 96 source guides

Damascus and Oxford c. 1366 CE and after

Ibn al-Shatir's Nihayat: which manuscript counts?

A fourteenth-century Damascus astronomer left a planetary theory that survives in several manuscripts. Learn why a manuscript on his astrolabe is not evidence for his Mercury model.