Ring of the Fisherman cardinal. Ring of the Fisherman The Ring of the Fisherman (Latin: "Annulus Piscatoris"; Italian: "Anello Piscatorio"), also known as the Piscatory Ring, is an official part of the regalia worn by the Pope, who is head of the Catholic Church and successor of Saint Peter who was a fisherman by trade. It used to feature a bas-relief of Peter fishing from a boat, a symbolism derived from the tradition that the apostles were "fishers of men" (Mark 1:17). The Fisherman's Ring is a signet used until 1842 to seal official documents signed by the Pope. A letter written by Pope
Ring (mathematics) and so is a polynomial ring. To give an example, let "S" be the ring of all functions from "R" to itself; the addition and the multiplication are those of functions. Let "x" be the identity function. Each "r" in "R" defines a constant function, giving rise to the homomorphism formula_133. The universal property says that this map extends uniquely to ("t" maps to "x") where formula_135 is the polynomial function defined by "f". The resulting map is injective if and only if "R" is infinite. Given a non-constant monic polynomial "f" in formula_111, there exists a ring "S" containing