Answer for Roadkill:
"The first year of the Islamic calendar began in 622 CE when
the Prophet Muhammad and his followers migrated from Mecca to Medina. This migration is called the "Hijrah." The Islamic year is then given as AH, which means "after the Hijrah.""
https://www.google.com/search?client=sa ... 8&oe=UTF-8
CE = Common Era (like AD)