The treatise on Antichrist made much noise among all the declared enemies of the Romish Church[531]. Michael Gettichius wrote to Ruarus, that he had only glanced over Grotius's book on Antichrist; but as far as he could judge by the first reading, that learned man, who was possessed of such an excellent genius, and such singular erudition, had no other intention than to engage the Learned in a further enquiry concerning Antichrist; and to determine them to attack with greater strength the Romish Antichrist; or, if he wrote seriously, he wanted to cut out a path for going over, without dishonour, to the Papists. Ruarus answers this letter, Dec. 16, 1642, from Dantzic. "I have always, he says, looked on Grotius as a very honest, and at the same time a very learned man. I am persuaded that love of peace engaged him in this work. I don't deny but he has gone too far; the love of antiquity perhaps seduced him: no Remonstrant, that I know of, has as yet answered him; but he has been confuted by some learned Calvinists, particularly Desmarets, Minister of Boisleduc, who has written against him with much bitterness." Grotius's work was printed in 1640, with this title: _Commentatio ad loca quaedam Novi Testamenti, quae de Antichristo agunt aut agere putantur, expendenda, eruditis._ It contains an explanation of the second chapter of the second epistle of St. Paul to the Thessalonians, in which he undertakes to prove, that the Man of Sin, there mentioned, is the Emperor Caius Caligula, who wanted to place his statue in the temple of Jerusalem, as may be seen in Philo; and was desirous to be thought a God, as Philo and Josephus relate. He afterwards explains the eighteenth verse of the second chapter of the first epistle of St. John. _You know that Antichrist is come, and that there are many Antichrists._ He thinks the Antichrist already come was Barchochebas, and that the other Antichrists are Simon the Magician and Dosithaeus. The beast, in the thirteenth chapter of the Revelation, is, according to him, Rome pagan; the power, which is given to it for forty-two months, signifies Domitian's persecution, which lasted three years and a half. The beast that ascended out of the bottomless pit, mentioned chap. xi. ver. 7. is magic, and Apollonius Thyanaeus: in fine, he finds the famous number 666, mentioned in the last verse of the thirteenth chapter of the Apocalypse, in Trajan's name, who was called Ulpius, of which the numeral letters form the number 666.