Answer:
1) He felt the Christians were the infidels who needed to be forced out of the Holy Land. - In a way, Saladin launched his own crusade and fought the christians in Egypt and Palestine. His victory at the Battle of Hattin was decisive. At the end of the crusades, the christians were expelled from the Holy Land.
2) Pope Urban II - He convinced many european noblemen and warriors, especially from France, to retake the Holy Land and aid the Byzantine Empire against the muslim armies.
3) Peter the Hermit - He was a french priest. He not only led the People's Crusade, but also participated in several massacres against the jews who lived in the Holy Roman Empire (modern-day Germany).
4)To secure his own power over the church - a few years before, the catholic church and the eastern orthodox church had split, and this reduced the power and authority of the Pope. Besides, Pope Urban II had to face the opposition from Antipope Clement III, who questioned his authority. Pope Urban II therefore needed to strengthen his power.
5) Louis IX - He was king of France and led the Seventh Crusade. They were defeated in Egypt and sent back to France. He tried again and took part in the eight crusade, but died of disentery shortly after.
6) Richard fought against Saladin, but eventually participated in a truce with him - Richard had a victory against Saladin, but with years, the war exhausted both leaders and a truce was negotiated. This treaty is known as the Treaty of Jaffa and allowed christian pilgrims to travel to Jerusalem, which remained under muslim control.
7) Alexius I Comnenus - who was the Byzantine Emperor at the time.
8) The Duke of Lower Lorraine, who is credited for retaking Jerusalem from Muslim Turks - He was a french nobleman and Knight, and seiged and took Jerusalem in 1099.
9)Jerusalem has a large mountain range at the northern point - These mountains are known as the Judaean Mountains, and border Jerusalem to the north.
10)Jerusalem has a mild climate, which attracted many people to move to the area - Jerusalem is located at 700 meters above sea level (around 2000 feet above sea level), and elevation causes air to cool down. This is why Jerusalem has a milder climate that most the sorrounding cities like Amman or Damascus.
