He eventually became a partner in this business, and he held partnerships in the distilling firm of John Porter & Co. and the Belfast Insurance Co. By the time he reached adulthood, Tennant was a very prosperous businessman.

[4] The Society of United Irishmen, originally proposed by Tennant's friend in Dublin, William Drennan, was formed in Belfast by a group of the town's more radical Presbyterian reformers, enthused by the French Revolution and Thomas Paine's vindication of The Rights of Man.

[6] [7] According to Wolfe Tone, Tennant had been a member of a pre-United Irishmen secret society in Belfast which included McTier and Haslett, as well as Samuel Neilson and Gilbert McIlveen.

[8] This was the Jacobin Club described by William Drennan's sister Martha McTier in 1795 as an established democratic party in Belfast, composed of "persons and rank long kept down" and chaired by a "radical mechanick".

[9] In April 1795 Earl Fitzwilliam, Lord Lieutenant for just fifty days, was recalled to London for publicly urging support for Catholic Emancipation.

Established on progressive principles, its mission was to render "less expensive the means of acquiring education; to give access to the walks of literature to the middle and lower classes of society; [and] to make provision for the instruction of both sexes.