DEFENSOR FIDEI. - Title granted by Leo X by the bull *Ex supernae dispositionis arbitrio* of 11 Oct. 1521 to Henry VIII of England, in recognition of the merits he had acquired for the defense of the Catholic faith with his work *Assertio septem Sacramentorum contra M. Lutherum* (1521).
The title was confirmed to him in 1523 by Clement VII; but later withdrawn, after the king’s schismatic defection, by Paul III; however, a decision of Parliament in 1544 not only confirmed it to him but also declared it hereditary for all his successors. Even today it is found expressed by the abbreviation *d. f.* on the royal coat of arms and on coins.