Apocalypse 13:1

I saw a beast coming out of the sea. By this first beast several understand antichrist, as St. Irenæus, lib. v. chap. xxviii. and St. Gregory, lib. xxxi. Moral. chap. xli. But this is not certain. By the other beast¹ coming up out of the earth, (ver. 11) many understand antichrist's false prophet, some famous impostor and magician in antichrist's time, who will do great wonders and signs. The seven heads and ten horns, may again signify a great number of kings and princes, who shall be overcome by antichrist, and submit themselves to him. The dragon, or devil, gives that great power to antichrist, signified by the different parts of the beast, some like to a leopard, others to a bear, and others to a lion. The head wounded to death and cured, is either antichrist himself or some one of those heads or kings, cured by the devil and diabolical arts after a mortal wound. (Witham)

This first beast, with seven heads and ten horns, is probably the whole company of infidels, enemies and persecutors of the people of God, from the beginning to the end of the world. The seven heads are seven kings, that is, seven principal kingdoms or empires; which have exercised, or shall exercise, tyrannical power over the people of God: of these, five were then fallen, viz. the Egyptian, Assyrian, Chaldean, Persian, and Grecian monarchies: one was present, viz. the empire of Rome: and the seventh and the chiefest was to come, viz. the great antichrist and his empire. The ten horns may be understood of ten lesser persecutors. (Challoner)

¹ Though St. Irenæus, and also St. Gregory, (lib. xxxi. mor. chap. xli.) by the first of these two beasts understand antichrist, and others would have antichrist to be meant by one of the two, yet this is not to be looked upon as absolutely certain, not being witnessed by the consent of primitive Fathers. The ancient Fathers, especially in the exposition of obscure prophecies, many times give us no more than their private opinions, or suspicions and conjectures, as St. Augustine expressly takes notice in the 20th book de Civ. Dei[City of God], (chap. xix. tom. 7. p. 597. Nov. Ed.) where he speaks of antichrist: so that though St. Irenæus had seen St. Polycarp, who was a disciple of St. John the evangelist, yet he delivers us divers things concerning antichrist, which are no more than his private opinions and conjectures, in which others do not agree with him; as that antichrist shall be of the tribe of Dan; that he shall sit in the temple of Jerusalem. He was also in an error as to Christ's reign of a thousand years upon the earth with his elect. Arethas, bishop of Cæsarea, in Cappadocia, in the sixth age[century], in his commentary on the Apocalypse, (tom. vi. Bib. Patrum, Edit. Colon) speaking of this opinion, that some would have the first beast (Apocalypse xiii. 1.) to be antichrist, and others the second beast, only says: quidam sic accipiunt, &c.