Famous birthdays, deaths and events of 1099
- July 10 - El Cid, of Castile (b. 1044)
- June 7 - The First Crusade: The Siege of Jerusalem begins.
- July 8 - First Crusade: 15,000 starving Christian soldiers march in religious procession around Jerusalem as its Muslim defenders look on.
- July 15 - First Crusade: Christian soldiers take the Church of the Holy Sepulchre in Jerusalem after the final assault of a difficult siege.
- July 22 - First Crusade: Godfrey of Bouillon is elected the first Defender of the Holy Sepulchre of The Kingdom of Jerusalem.
- August 12 - First Crusade: Battle of Ascalon