The Fall of Outremer
Baibars
I cover this subject in a bit more detail in my essay on Outremer, but a refresher is in order here. Baibars tried repeatedly to capture the principal castles and cities of the Crusader States. He was thwarted principally by the constant threat of a new Mongol invasion. He was, however, successful in driving the Mongols out of Syria and Palestine, and in destroying Armenia. Here are his principal conquests.
Aleppo fell to Baibars in 1261, after which he invaded Armenia. The threat of the Golden Horde was too great, however, and he pulled back. In 1263 he captured Nazareth and attacked Acre but had to break it off.
He launched a new offensive in 1265, capturing Caesarea, Haifa and Arsuf in that year. The following year he took the two great castles of Safed and Toron. Then he invaded Cilicia and sacked its capital, Sis.
In 1268 he took Jaffa, then Castle Beaufort, and then Antioch. The slaughter in Antioch was terrible and reduced a once-great city to the status of a village. It never recovered.
But Acre held out against him. He tried twice more, getting as far as attacking the walls, but never being strong enough to settle in for a serious siege. He did manage to do damage in other forms, though. He had Philip of Montfort assassinated in 1270 and tried to do the same to Edward of England. Baibars died in 1277.