of the Roman Curia or important episcopal sees throughout the world. As a whole, the cardinals compose a College of Cardinals which advises the Pope, and those cardinals under the age of 80 at the death or resignation of a Pope elect his successor. Their heraldic achievement is surmounted by the red galero and tassels as a form of martyred position in the Church. Not all cardinals are bishops. Domenico Bartolucci, Karl Josef Becker, Roberto Tucci and Albert Vanhoye are examples of 21st-century non-bishop cardinals. The 1917 Code of Canon Law introduced the requirement that a cardinal must be at least a priest. Previously, they need only be in minor orders and not even deacons. Teodolfo Mertel, who died in 1899, was the last non-priest cardinal. In 1962, Pope John XXIII made it a rule that a man who has been nominated a cardinal is required to be consecrated a bishop, if not one already, but some ask for and obtain dispensation from this requirement. It is rare that the Pope will appoint Cardinals who are priests only and not consecrated as a bishop. The 1917 Code of Canon Law, continuing the tradition observed, for instance, at the First Vatican Council, laid down that cardinals have precedence over all other prelates, even patriarchs. The 1983 Code of Canon Law did not deal with questions of precedence. The cardinalate is not an integral part of the theological structure of the Catholic Church, but largely an honorific distinction that has its origins in the 1059 assignation of the right of electing the Pope exclusively to the principal clergy of Rome and the bishops of the seven suburbicarian dioceses. Because of their resulting importance, the term cardinal (from Latin cardo, meaning "hinge") was applied to them. In the 12th century the practice of appointing ecclesiastics from outside Rome as cardinals began. Each cardinal is still assigned a church in Rome as his "titular church" or is linked with one of the suburbicarian dioceses. Of these sees, the Dean of the College of Cardinals holds that of Ostia, while keeping his preceding link with one of the other six sees. Traditionally, only six cardinals held the rank of Cardinal Bishop, but when Eastern patriarchs are made cardinals, they too hold the rank of Cardinal Bishop, without being assigned a suburbicarian see. The other cardinals have the rank either of Cardinal Priest or Cardinal Deacon,