Short answers, pulled from the story.
The Kingdom of Jerusalem began on the 15th of July 1099 when Crusaders captured the city. Godfrey of Bouillon became the first leader by taking the title Advocatus Sancti Sepulchri instead of wearing a crown.
Old French served as the lingua franca among the elite while Latin functioned as the official language for church and legal matters. The majority population spoke Greek or Arabic including native Christians, Muslims, Jews, and Samaritans.
Baldwin II established the Knights Hospitaller and the Knights Templar to provide crucial defense capabilities against Muslim invasions from Egypt and Syria. These organizations grew powerful over time controlling large estates and fortresses with independent command structures.
Benjamin of Tudela recorded approximately 1,500 Samaritans across the kingdom with about 1,000 in Nablus alone. His estimates suggest the Samaritan population may have been larger than the Jewish community at that time making it unique in history.
The army of the Kingdom of Jerusalem was destroyed on the 4th of July 1187 at the Battle of Hattin. This disaster led to Saladin overrunning nearly the entire kingdom except for Tyre and effectively ending the first phase of the crusader state.
Mamluk sultan al-Ashraf Khalil ruled from 1290 to 1293 when he systematically destroyed remaining Crusader strongholds culminating in the destruction of Acre itself in 1291. Earlier Mamluk sultans like Baibars reigned from 1260 to 1277 while destroying other fortresses before this final event.