In his Diatribae upon the first part of the late History of Tithes, 1621, he entered directly into the controversy of the day, in an attempt to beat John Selden on tithes. Controversy against Catholic teachers in his parish was answered in a pamphlet called A Gag for the New Gospel, by Matthew Kellison; he replied in A Gagg for the New Gospell? No. A New Gagg for an old Goose, 1624. The 'Gagg' had contained forty-seven propositions which it attributed to the Church of England. Of these Montagu only allowed eight to be her true doctrine, again demarcating Anglican doctrine on two fronts. He also issued a defensive work, rebutting Marco Antonio de Dominis who charged Montagu with supporting "praying unto saints and angels in time of need". It proved a magnet for controversy, with answer after answer coming from the presses. There was a complaint from two East Anglian ministers, John Yates and Nathaniel Ward; Ward had been overseas to 1624, and it was a few years later that he became vicar of Stondon Massey, close to Stanford Rivers in Essex, and one of Thomas Hooker's anti-Laudian group. The House of Commons referred the book to Abbot. Abbot applied for authority to the King, and remonstrated with Montagu. But James himself approved of his work. "If that is to be a Papist" he said, "so am I a Papist". The matter did not rest with the King's death. Appello Controversy around Montagu's positions played an important part in the period 1625–9, both in publications and in political moves, and was one of the issues setting the tone for the reign of Charles I. Montagu had the open support of three bishops (John Buckeridge, John Howson, and William Laud). His Appello Caesarem: a just Appeale from two unjust Informers (London, 1625) came out with an imprimatur from Francis White, dean of Carlisle, after George Abbot's refusal to license it. It was partly written in self-justification, but also attacked some Calvinist tenets, including the perseverance of the saints. Francis Rous defended double predestination against Montagu in Testis Veritatis (1626). The House of Commons took up the matter, and accused the author of dishonouring the late King (James I). A debate on the matter was followed by Montagu's committal to the custody of the serjeant-at-arms. He was, however, allowed to return to Stanford Rivers on giving a bond. Charles then made