Saladin's forces entered Jerusalem in 1187 after a series of events that began with the Battle of Hattin. Following his victory at Hattin, Saladin's armies gained control over much of the surrounding territory, weakening the Crusader states in the region. The way was then open for Saladin to lay siege to Jerusalem.

The city of Jerusalem was under the control of the Crusaders, and its defenses had been significantly weakened due to the defeat at Hattin. With Saladin's forces surrounding the city, the Crusaders were left in a dire situation. Negotiations took place between the defenders of the city and Saladin's forces, but these negotiations did not result in an agreement.

After a prolonged siege and with limited hope of relief, the defenders of Jerusalem eventually surrendered to Saladin on October 2, 1187. The terms of surrender included a payment by the Christian inhabitants to secure their freedom and safe passage out of the city, similar to the terms often negotiated in medieval sieges. The exact details of how Saladin's forces entered the city might vary in historical accounts, but it's likely that they marched into Jerusalem after the terms of surrender were agreed upon.

Saladin himself is said to have entered the city a few days after its surrender, on October 17, 1187. He entered as a victorious conqueror but also aimed to show restraint and respect for the city's significance to various religious groups. The holy sites of the city were especially important, as Jerusalem holds great religious significance for Muslims, Christians, and Jews alike.

The fall of Jerusalem to Saladin marked a major event in the history of the Crusades and had a profound impact on the region's political and religious landscape. It triggered the launching of the Third Crusade by European leaders to try to recapture the city and reestablish Christian control over the Holy Land.