Papal Bull (L. Lat. oulla, a seal), one of the forms in which the pope issues his ordinances. It differs from a brief in that the latter, though of equal authority, is issued with less solemnity. Briefs are sealed with red wax, stamped with the ring of the fisherman. The seal of a bull is of lead or gold, stamped on one side with the effigies of Saints Peter and Paul, and on the other with the name of the reigning pope, and attached to the document by strings. The two acts ditfer also by the subscription, salutation, and apostolic benediction, which are simpler in the brief; and by the date, which is taken from the modern calendar for briefs, and from the Roman calendar for bulls. Bulls are commonly designated from the words with which they commence, as the bull In ccena Domini, which was formerly read publicly at Rome on Holy Thursday, and contains a general excommunication against heretics and those contumacious and disobedient to the holy see. Its publication was suspended by Clement XIV. in 1773. Among the bulls most celebrated in history are the Clericis laicos, given in 1296 by Boniface VIII., and which began his contest with Philip .the Fair; the Execrabilis, issued by Pius II. in 1460, to interdict appeals to future councils; the ExsurgeDomine, directed in 1520 by Leo X. against Luther, who burned it at Wittenberg; the Cum occasione, by which Innocent X. condemned the five propositions of Jansenius, in 1653; the Unigenitus, issued by Clement XL in 1713, against the "Moral Reflections" of Quesnel; the Post dlurnas, by which Pius VII. in 1800 established a new judiciary order in the states of the church; the Ineffabilis Deus, by which Pius IX. in 1854 defined the dogma of the immaculate conception; and the AEterni Patris, June 29, 1868, by which he convoked the oecumenical council of 1869-'70, which defined and affirmed the doctrine of papal infallibility. - Bullce dimidice, or half bulls, are bulls issued by the pope before his coronation, and so called from the fact that the lead or gold is stamped only on one side.