Castillo de los Templarios (Castle of the Knights Templar) in Ponferrada. The Knights Templar were among the most wealthy and powerful of the Western Christian military orders and were among the most prominent actors of the Christian finance - i.e., they lent money to various kings and nobles to finance their wars.
Officially endorsed by the Catholic Church around 1129, the Order became a favoured charity throughout Christendom and grew rapidly in membership, money and power. Templar Knights, in their distinctive white mantles with a red cross, were among the most skilled fighting units of the Crusades, while the non-combatant members of the Order managed their large banking system.
King Philip IV of France was deeply in debt to the Order, and came up with an interesting way to clear his debts. In 1307, many of the Order's members in France were arrested, tortured into giving false confessions, and then burned at the stake. Under pressure from King Philip, Pope Clement V disbanded the Order in 1312 (after originally declaring, truthfully, that the Knights were innocent!)