The Kingdom of Jerusalem was a crusader state in the Levant that was established in 1099 after the First Crusade. The kingdom was ruled by Frankish and Italian nobles who answered the Pope's call to arms to seize the city of Jerusalem from the Muslim Saracens, and Western European pilgrims arrived to help in the expansion of the kingdom to include much of the Levantine coastline, with its core being the regions of Judea and Samaria (with Jerusalem and Nablus as the capitals of the two regions). At its height in 1135, Jerusalem stretched from southern Lebanon in the north to the northern Sinai in the south, with the County of Tripoli being a vassal state of the kingdom. In 1187, the kingdom was almost entirely overwhelmed by the Ayyubid sultan Saladin, who captured Jerusalem, but the Third Crusade led to the 1192 re-establishment of the kingdom with Acre as its capital. Jerusalem cycled through many rulers and regents over the years, with unstable politics contributing to the weakness of the kingdom. The Mamluks conquered much of the kingdom in the 13th century, and the 1291 fall of the capital of Acre led to the end of the Kingdom of Jerusalem, the last crusader state.