On May 18, 1268, the Principality of Antioch, a Crusader State, fell to the Mamluk Sultan Baibars in the Battle of Antioch. A short excerpt:
"The Mamluk Conquest
As the 13th century CE wore on, so the threat to the Crusader States increased. The Seventh Crusade (1248-1254 CE) attacked Egypt and was a flop, a situation not improved by the dismal Eighth Crusade (1270 CE). Between the two, the Crusades leader, Louis IX of France (r. 1226-1270 CE), did stay on in the Middle East and he helped to refortify some of the cities of the Kingdom of Jerusalem, notably Sidon, Jaffa, and Caesarea. However, in 1268 CE Antioch was sacked by the Mamluks who were based in Egypt and led by the gifted former general Baibars (r. 1260-1277 CE). The region saw a brand new threat, too, the ever-expanding Mongol Empire. The Mongols, moving relentlessly westwards, made raids on Ascalon and Jerusalem. When a Mongol garrison was established at Gaza, an attack on Sidon quickly followed in August 1260 CE.
Aid came from an unexpected quarter when Baibars pushed the Mongols back to the Euphrates River but he then took over much of the Latin East so that only two pockets remained around Acre and Antioch. Finally, mighty Acre fell in 1291 CE and the Kingdom of Jerusalem and the Latin East now only existed as a refuge on Cyprus; what was left of the Crusaders States was absorbed into the Mamluk Sultanate which would rule in the region until 1517 CE."