Answer
The Kingdom of Jerusalem was a crusader state that existed from AD 1099 to 1291.
During the time of Christ, Jerusalem was under the control of the Roman Empire. This control persisted until the 7th century. Following the conversion of Constantine in the early 4th century, Christianity was recognized as a legal religion and eventually became the state religion. Emperor Constantine constructed churches and shrines in Jerusalem and Palestine to honor holy sites, turning Jerusalem into a significant destination for Christian pilgrimages.
In the early 7th century, Jerusalem slipped from Roman Empire control and came under Persian and later Arab-Muslim rule. Islam also revered Jerusalem as a sacred place, erecting shrines and mosques to commemorate historical events. The Dome of the Rock stands out as the most prominent shrine, constructed directly on the temple mount. Under Arab governance, Jerusalem thrived, initially showing tolerance towards Christians. However, this tolerance diminished over time.
In the early 11th century, a ruler of the Fatimid Dynasty ordered the destruction of all churches in Jerusalem. This action incensed Christians across Europe, leading to the First Crusade (1095–1099) proclaimed by Roman Catholic Pope Urban II. A crusade was not just a military campaign but also held spiritual significance. Initially intended to aid the Byzantine Emperor against Turkish Muslim invaders, the focus of the First Crusade shifted towards reclaiming and freeing Jerusalem. In 1099, the Crusader army besieged and seized Jerusalem, resulting in the massacre of many Muslim and Jewish residents.
The conquered land was divided into crusader states—small territories or outposts governed by Western Europeans. The Kingdom of Jerusalem was among these crusader states. Christian settlers migrated to Jerusalem to repopulate and reconstruct the city, reigniting Christian pilgrimages. This arrangement persisted until 1187 whenIn the city and several other Crusader states were captured by the Kurdish Muslim Saladin; fortunately, his official policy was one of tolerance towards all religions. Although Jerusalem itself was in Muslim hands, the Kingdom of Jerusalem still existed as the small city of Acre on the coast.
This Muslim dominance led to the Third Crusade, which aimed to expel Muslims from the Holy Land and reaffirm Christian/European authority. The Crusaders were unable to retake the city but reached a treaty with Saladin to permit pilgrimages. Conflict among different Muslim factions was frequent, and the city changed ownership multiple times. Although the city briefly returned to Christian possession about 50 years later, Acre was the final remaining trace of the Kingdom of Jerusalem. It was conquered by the Muslims in 1291.
Jerusalem and Palestine remained under Muslim control until the 20th century when the United Nations partitioned Palestine, establishing a Jewish state—modern Israel—after World War II.