Protector /(?)/

Pro·tect·or

Protector

n.
  1. One who, or that which, defends or shields from injury, evil, oppression, etc.; a defender; a guardian; a patron.
    For the world's protector shall be known.
  2. One having the care of the kingdom during the king's minority; a regent. (Eng. Hist.)
    Is it concluded he shall be protector !
  3. A cardinal, from one of the more considerable Roman Catholic nations, who looks after the interests of his people at Rome; also, a cardinal who has the same relation to a college, religious order, etc. (R. C. Ch.)

Phrases & Compounds
Lord Protector
the title of Oliver Cromwell as supreme governor of the British Commonwealth (1653-1658).