The Order of Santiago (aka Orden de Santiago), was founded by King Ferdinand II of Leon in 1230 (as a military Religious Order to assist him in maintaining his claim to the throne). They wore the White mantle-apron with The Red St. James Cross on their front. They followed The Rule of St. Augustine and were under Papal Authority. They however had "relaxed" the rule of marriage. Many of The Order's family members stayed with them in the many garrisons they managed. The Order was part of the 3 Great Military Orders of Spain (fighting primarily to repeal Moorish/Muslim incursions).
A Candidate had to prove his Noble blood by 4 generations (using their surnames). The Order felt that "blood" established them. Candidates could do no manual labor and like their "blood proof", they had to establish their Catholicism going back 4 generations (without any past family members under any heresy charges). Many of they "rules" would be removed by The King (later in The Orders history). The Order was responsible for founding many Monasteries and Abbeys throughout Granada. Unlike many other Orders, they survived disbandment in the 16th Century. They still exist today as a philanthropic religious organization.