The question does not make much sense. Christianity is a religion; it cannot be seized. If the question is trying to ask why Saladin seized Jerusalem from the Christians, it was because the city had been under Islamic control for over 300 years and many Muslims believed that they had the right to govern it as they had for centuries.
because he said it was also a holy city for Muslims as the Dome of the Mosque is there
The question does not make much sense. Christianity is a religion; it cannot be seized. If the question is trying to ask when Saladin seized Jerusalem from the Christians, it Saladin reconquered the city on 2 October 1187, when the (Christian) Kingdom of Jerusalem relented after two week siege.
Saladin took Jerusalem in the Second Crusade, specifically in October of 1187. In the Third Crusade, Saladin started off in control of Jerusalem and Richard the Lionheart abandoned his marches on Jerusalem upon signing the Treaty of Jaffa. As a result, Saladin never lost control of Jerusalem during the Third Crusade and never had to retake it.
Jerusalem fell to Muslim forces under Saladin.
1187
1187
Saladin captured the Christian but then let them return back to their native lands
Saladin
1187
Saladin .
Saladin was not in a crusade. He was a great Muslim commander who fought against the crusades of the christians who ruled Jerusalem.
He took over Jerusalem but was bad
Jerusalem