What is an apostolic bull?
The word “bull” refers not to an animal, but to the seal that is placed on the most important of papal letters. The Holy See retains the ancient custom of securing important letters with a seal. Many times, a seal is made of wax, which is poured over the closed letter and imprinted with the insignia of the sender. In the case of an important letter issued by the Holy See, the letter is sealed with a bulla, which is a leaden seal, and imprinted with the Popes insignia. Bishops are officially appointed by means of an apostolic (or papal) bull. Also, the document that announces beatifications or canonizations is also the papal bull.
