Who they were
Salah al-Din Yusuf ibn Ayyub, known as Saladin, was born in 1137/38 in Tikrit, in modern Iraq, to a Kurdish military family, and died in 1193 in Damascus. He rose in the service of Nur al-Din, the ruler of Syria, was sent to Egypt, and became vizier of the Fatimid caliphate in 1169.
What they did
In 1171 he abolished the Shia Fatimid caliphate, restoring Sunni Islam in Egypt, founded the Ayyubid dynasty that ruled Egypt and later Syria, and began building the Cairo Citadel. In 1187 he destroyed the Crusader army at the Battle of Hattin and retook Jerusalem after 88 years of Crusader rule; medieval accounts on both sides noted how relatively bloodless his takeover was, in contrast to the massacre when the Crusaders took the city in 1099. The fall of Jerusalem triggered the Third Crusade (1189–92), in which he fought King Richard I of England to a truce — the Treaty of Jaffa of 1192 — that left Jerusalem in Muslim hands while securing Christian pilgrimage rights.
Legacy
Both Muslim and European medieval tradition gave him a reputation for generosity and chivalry. He stands as a central figure of Islamic history, and the Ayyubid state he founded in Egypt set the stage for the Mamluk sultanate.