Templars and early banking

"Medieval banking existed in a moral gray area from the 10th century until well into the 15th century. Before this period, Europe was too poor to support an extensive, morally corrupting banking system. By the end of the 15th century, the major Italian banking houses had learned ways of circumventing Church disapproval in their financial transactions. When they could not find loopholes, they increasingly violated the religious prohibitions. 

Financing the crusades - the role of the military orders

"Through the military orders of warrior-monks, the church provided directly for the defense of the Holy Land. The most important of these orders were the Knights of the Temple and the Brethren of the Hospital of St. John, although for a time the Teutonic Knights added their strength and resources to the common task.