Antioch is a city on the Orontes river in Turkey. It was founded in classical times by Seleucus I, one of the generals of Alexander the Great. In the 12th and 13th centuries Antioch was an important Crusader State, a principality of the Kingdom of Jerusalem.
In 638CE it was conquered by the Muslims of the Arab caliphate and became an important forward outpost in their wars with the Byzantine empire. In 969 the Byzantines recovered the city and although Seljuk Turks recaptured it in 1084, they were only to hold it for a short period.
During the First Crusade Antioch was besieged for nine months; when it fell the city was given to Bohemond of Taranto who was believed responsible for the capture, by the Christian act of bribing one of the city's sentry captains; it became the capital of a Latin principality for almost 2 centuries (finally falling to the Egyptian Muslims after another siege in 1268).
A notable legend sprang from Antioch during the siege -- immediately after the city had been taken, a Muslim army arrived, and set a siege. A monk, Peter Batholemew, then claimed that he had discovered the Holy Lance (that with which Jesus Christ had been struck whilst on the Cross) hidden in the city's cathedral. Thus emboldened, the Crusaders broke the siege and the Lance became a relic of the Western Church.
After Bohemond was captured, in c.1100, the city was governed by his nephew Tancred, who carried on his uncle's plan to expand the territory subject to the city. On his release, unable to conquer Aleppo, frustrated by what he felt was duplicity by the Byzantines, and seeking to obtain more supporters, Bohemond made Tancred his formal regent, and sailed for Europe, to recruit. He returned, made one unsuccessful attempt to capture a city, and went home, to die there, leaving Tancred to succeed him in Antioch.
By now Tancred had added the regency of Edessa to his titles, and had made himself a tempting target for other Crusader lords looking for a domain. Around 1109, he was compelled, by military force, to yield Edessa to its former lord, Baldwin of Bourcq, and to acknowledge the Kingdom of Jerusalem as the principal power in Outremer.
Tancred died in 1112, after wars with his Muslim neighbours, and his successor as regent was one Roger, holding for the infant (and absent) Bohemond II. Roger's death led to the interesting position of the regency being taken over by Baldwin of Bourcq (by then Baldwin II of Jerusalem. Bohemond the younger reached Antioch in 1226, and took over rule of the city, to die four years later, in war in Cicilia, leaving a young daughter, Constance. Again a regency was required.
Baldwin II was the first of Constance's regents, and after his death in 1131, his daughter Alice, widow of Bohemond II, succeeded in taking power (aided by the lords of Tripoli and Edessa, both of whom wanted Jerusalem's power limited). Fulk the Younger, husband to Baldwin's heiress, Melisende, rode north to claim the regency -- in the event in 1136 he married Constance to the 36-year-old Raymond of Poitiers.
Prince Raymond immediately became embroiled in Cilicia; the Byzantine emperor, John II took umbrage and used an army to compel homage from Raymond, as well as obtaining an agreement to exchange the city for three Muslim cities (Aleppo, Shiazar and Homs) once John had captured them. When he failed to do so (and decided that his failure was due to a lack of support from the Antoichenes), John returned and seized the city, to be driven out by a popular revolt.
From 1144 the Muslim general Nur ad-Din began attacks on Edessa and Antioch. The call went out for a Second Crusade -- Europe responded in 1148, but their troops were gone by the following year and Nur ed-Din pressed, attacking the fortress of Inab; Raymond was killed in a counter-attack.