Ecclesiastical heraldry refers to the use of heraldry within the Christian Church for dioceses and Christian clergy. Initially used to mark documents, ecclesiastical heraldry evolved as a system for identifying people and dioceses. It is most formalized within the Catholic Church, where most bishops, including the Pope, have a personal coat of arms. Clergy in Anglican, Lutheran, Eastern Catholic, and Orthodox churches follow similar customs, as do institutions such as schools and dioceses.