In 1095 Pope Urban II launched the First Crusade, one of the more successful and momentous military campaigns of the Middle Ages. It not only led to the foundation of four Crusader principalities in the Middle East, but also inspired numerous other crusades, which together wrought crucial cultural, political, and economic changes both in Europe and in the Middle East.

Yet in May 1098 the First Crusade – and the entire Crusader movement – was almost stillborn, despite the enormous material and cultural resources already invested in it. The so-called Peasants' Crusade, after cutting a swath of destruction through Central and Eastern Europe, massacring Jewish communities and pillaging Christian ones, was easily wiped out by the first armed enemy it encountered: the Seljuk Turks of Nicea (1096). The better organized and more heavily armed Princes' Crusade that crossed into Asia in the following year fared somewhat better. After helping the Byzantines capture Nicea, they defeated a Seljuk army at Dorylaeum (1097), and then marched across Asia Minor, meeting little opposition until they arrived before the walls of Antioch in October 1097. But there the crusade ground to a complete halt.

Antioch was one of the ancient metropolises of the Middle East. Founded as the capital of the Seleucid Empire, it later became the principal city of the Roman Levant, and one of the three original Christian patriarchates. The Muslims conquered it in 637. In 969 Christian soldiers in the service of the Muslim governor betrayed several towers in Antioch’s wall to a small Byzantine force, which thereby reconquered the city. In 1085 Antioch withstood the assaults of the Seljuk leader Suleyman, but either Philaretos, its Armenian governor, or Philaretos’s son, turned traitor. Under cover of night a Seljuk force was secretly admitted into the city, and at dawn of the following morning the citizens awoke to find themselves under Turkish rule.