CRUSADE

[noun] [C] - a long and determined attempt to achieve something which you believe in stronglyThey have long been involved in a crusade for racial equality.She was a leading light in the crusade against illiteracy.The President has embarked on a moral crusade to encourage parenthood within stable marriages.The Crusades were the holy wars fought by the Christians against the Muslims, often in Palestine, in the 11th, 12th, 13th and 17th centuries.The Middle East had become known to Europeans during the 11th-13th century Crusades.