ordained by Bangor presbytery on 24 Sept. as successor to Andrew George Malcom, D.D. [q. v.] In this pastoral charge he remained till his death.
From the beginning of his settlement at Dunmurry, Montgomery engaged in tuition, and from 1815 boarded pupils in his house. On 3 Oct. 1817 he was elected head-master, in succession to James Knowles [q. v.] of the English school in the Belfast Academical Institution, his congregation agreeing that he should reside there. He had just declined an invitation, made through Archibald Hamilton Rowan [q. v.], to preach on trial at Killeleagh, co. Down, the charge to which Cooke was subsequently elected. He held the mastership till June 1839, and exercised much influence on the literary education of Ulster. Children of all presbyterian ministers he taught without fee. His connection with the institution naturally led him to vehemently repel the attacks made upon it as a 'seminary of Arianism' by Cooke from 1822.
Montgomery's first appearance as a debater in the general synod of Ulster was in June 1813, when he espoused the cause of William Steel Dickson, D.D., [q.v.], and helped to break the power of Robert Black, D.D. [q.v.], who, though a liberal in theology, had hitherto swayed the synod in the interests of political conservatism. In 1816 Montgomery was a candidate for the clerkship of synod, but withdrew in favour of William Porter (1774-1843), minister of Newtownlimavady, co. Deny. On 30 June 1818, at an unusually early age, he was elected moderator of the general synod.
Since 1783, owing to the action of William Campbell, D.D. [q. v.], subscription had ceased to be in full force. Ten of the fourteen presbyteries composing the synod treated subscription as optional. The result was a considerable amount of undemonstrative heterodoxy. A code of discipline, which had been contemplated since 1810, was adopted by the general synod at Moneymore, co. Derry, in 1824. It provided that presbyteries should ascertain 'soundness in the faith,' either by subscription or by examination. This compromise, suggested by Samuel Hanna, D.D. [q.v.], was accepted by all parties. But Cooke persistently sought to render the discipline more stringent. To defeat Cooke's policy was the object to which Montgomery devoted the marvellous resources of his commanding eloquence. The resulting struggle is described by Classon Porter as 'almost entirely a duel' between the two leaders, who were exactly matched in age ; though, if Latimer be right in affirming that Cooke was the son of John McCooke, and born about 1783, he was some years the senior.
At Strabane in 1827 Cooke carried a proposal that members of synod should declare whether or no they believed the doctrine of the Trinity. Only two voted 'Not.' Montgomery, who proclaimed himself an Arian, withdrew with others before the roll-call. His speech on this occasion, in favour of religious liberty, made a deep impression ; it was circulated over Ireland, and a service of plate was presented to him (18 June 1828) by members of various denominations, including Roman catholics. He had advocated catholic emancipation from 1813.
At Cookstown in 1828 James Morell, minister of Ballybay, co. Monaghan, carried a resolution for the appointment of a committee for the theological examination of all candidates for the ministry. This was meant to defeat the action of liberal presbyteries, and cut off the supply of Arian clergy. On 16 Oct. 1828 Montgomery and his friends adopted a 'remonstrance' at a presbyterian meeting in Belfast, attended by Cooke. The last of Montgomery's brilliant speeches in the general synod was delivered at Lurgan on 3 July 1829. The remonstrance was presented at a special meeting of synod, held at Cookstown on 18 Aug., and terms of separation were arranged at a conference on 8 Sept. The first meeting of the remonstrant synod was held on 25 May 1800 ; it consisted of three presbyteries containing seventeen congregations; it retained the 1824 code of discipline, and its ministers were secured in the possession of regium, donum.
Meanwhile Montgomery had visited the English Unitarians, and advocated catholic emancipation at public dinners in Manchester (December 1828) and London (January 1829). On his return he spoke in the same strain from the altar of St. Patrick's, Belfast, at a meeting (27 Jan. 1829) presided over by William Crolly, D.D. [q. v.], then Roman catholic bishop of Down and Connor. To O'Connell's agitation for repeal of the union he was strongly opposed ; his letter to O'Connell (1 Feb. 1831) was among the most powerful attacks upon the Liberator's position, and did much to alienate Irish liberals from his cause. He was in favour of Irish disestablishment, and gave evidence in this sense before parliamentary committees in 1832. He warmly supported the national system of education (established in 1831), which Cooke as warmly opposed. In 1833 he received the degree of LL.D. from Glasgow University. His last great personal encounter with Cooke was in connection with
