The Sovereign Order of Saint John of a Jerusalem is an order of knighthood, an ancient military order of chivalry, a noble and aristocratic class, a charitable and hospitaller organization, an exempt religious order of the Catholic Church, an hereditary association of men and women under Godly vows, a Christian state (such as France, England or Spain in the Middle Ages), and a republic (the oldest republic now in existence) in which the knights elect a Prince Grand Master from among their most distinguished brother knights. He thus becomes primus inter pares (the first among equals) and the supreme head of the Order a position he normally holds for life.