I was watching Kingdom of Heaven the other night. It's a great film, but too many people seem to be basing their history on it. In it Salah al-Din, a great general, whooped Balian of Ibelin at the Battle of Hattin (4 July 1187 - contemporary description here), and captured Jerusalem.
The result (only briefly alluded to at the end of the film) was the Third Crusade.
One of the great victories of that Crusade was the siege and Fall of Acre on the 12th July 1191. Saladin's troops were not up to defending the fortress, which was captured by the armies of Richard Coeur de Lion of England and Philippe Auguste of France.
A description from the Itinerarium Peregrinorum et Gesta Regis Ricardi can be found here. Richard's actions in victory were not a high-point of Christian-Muslim relations.
The Crusaders held Acre for exactly one century - it fell in 1291 to the Mamluk army of Al-Ashraf Khalil, sultan of Egypt, and with it the hopes of a Christian Kingdom of Heaven in the Holy Land.