These memorial plaques commemorate Thomas Sinclair, a Belfast merchant and Leader of Ulster Liberal Unionism, who composed the seminal Ulster Covenant of 1912.
Sinclair was born on September 23, 1838, to a strongly Presbyterian family with strong ties to north Belfast. The Sinclair family contributed much towards the cost of the Duncairn Presbyterian Church, now the Duncairn Centre and the Sinclair Seamen’s church in Sailortown was erected as a memorial to his uncle John. At just 28, Sinclair was elected and ordained an elder in the Duncairn congregation and a year later he was appointed its clerk of Kirk Session. His religion would play an influential role in his politics: The Ulster Covenant was directly modelled upon the Presbyterian Solemn League and Covenant of 1642.
He entered the family business – J. & T. Sinclair, Provision Merchants and Pork Curers but is best known for his influence in politics. Although Thomas Sinclair never stood for Parliament, as a wealthy and prominent Belfast citizen, he played a highly influential role in the affairs of the province.
Originally a supporter of W. E. Gladstone, he joined the Ulster Liberal party in 1868 and supported the 1870 and 1881 land acts but broke with the party over the use of Home Rule, In response to Gladston’s introduction of the first Home Rule Bill in 1886, Sinclair organised a large meeting of liberals in the Ulster Hall on 30 April and passed a resolution condemning the bill. He then formed the Ulster Liberal Unionist Association and, in his capacity as its chairman, organised the Ulster Convention, held in Belfast on 17 June 1892, which brought together 11,879 Ulster unionists of all backgrounds in the first mass protest against home rule. This meeting was an attempt to show Gladstone and Irish Nationalists that unionism was not a movement of disgruntled landlords who deliberately injected sectarian hatred to bolster their cause. The speeches were conciliatory towards Catholics and promoted an Irish identity, with a banner of ‘Erin go bragh’ above the main stage.

As a gifted writer, Sinclair was appointed on 25 September 1911 to a commission of five to frame a constitution for a provisional government of Ulster. The following year his was among the clearest and best argued of the contributions to the unionist party’s collection of essays, Against home rule (1912). Identifying Ulster as the six counties, he advanced the two-nation theory in refutation of nationalist claims and warned that Ulster would certainly resist until the end. Later that year he was given the crucial task of drafting the text of the Solemn League and Covenant, which pledged signatories to defeat home rule and refuse to recognise the authority of an Irish parliament. This document was signed by 471,414 people in the Belfast city hall on 28 September 1912.
Thomas Sinclair died less than two years after the covenant was signed on February 14, 1914 and was buried in Belfast three days later. Men from the four Belfast Battalions of the Ulster Volunteer Force accompanied his coffin down the Antrim Road to the City Cemetery. A memorial window was unveiled in Church House, the headquarters of the Presbyterian church on 8 June 1915 and the Sinclair Memorial Hall at Duncairn Presbyterian Church was opened in his honour on 10 September 1915. Sinclair’s portrait (above), by Frank McKelvey, now hangs in the Ulster Museum.