Complex sentence: The Kingdom of Jerusalem was founded in 1099 at the end of the First Crusade; it was the third of four Christian territories to be founded by the crusaders, following the County of Edessa and the Principality of Antioch, and followed by the County of Tripoli.
Split into simpler sentences: The Kingdom of Jerusalem was founded in 1099 at the end of the First Crusade. It was the third of four Christian territories to be founded by the crusaders, following the County of Edessa and the Principality of Antioch, and followed by the County of Tripoli.