ESMAIL JORJANI WAS an influential Persian physician and anatomist of the 12th century who did most of his writing after his seventh decade of life. Jorjani's comprehensive textbook of medicine, Zakhirey-e Khwarazmshahi (The Treasure of the Khwarazm Shah) was written in approximately AD 1112 and is considered to be the oldest medical encyclopedia written in Persian. This was an essential textbook for those studying medicine during this time. We describe the life and times of Jorjani and provide a translation and interpretations of his detailed descriptions of the cranial nerves, which were written almost a millennium ago. Medieval Persian and Muslim scholars have contributed to our current knowledge of the cranial nerves. Some of these descriptions, such as the eloquent ones provided by Jorjani, were original and have gone mostly unknown to post-Vesalian European scholars. Copyright © by the Congress of Neurological Surgeons.