William Tennent was born in 1759 in County Antrim, Kingdom of Ireland the eldest son of Reverend John Tennant a Scottish Presbyterian minister who settled in Ulster in the mid 18th century and was associated with the seceding faction of Ulster Presbyterians. As a young man he served as an apprentice with John Campbell, a Belfast merchant and banker. He joined the Belfast Chamber of Commerce in 1783, and was junior manager in the New Sugar House in Waring Street. 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.
The United Irishmen
The United Irishmen were initially founded as a group of liberal Protestant and Presbyterian men interested in promoting Parliamentary reform, and later became a revolutionary movement influenced by the ideas of Thomas Paine and his book 'The Rights of Man'. In 1791 Theobald Wolfe Tone published the pamphlet 'Argument on Behalf of the Catholics of Ireland' where he set out that religious division was being used to balance "the one party by the other, plunder and laugh at the defeat of both." He put forward the case for unity between Catholic, Protestant and Dissenter. This pamphlet was read by a group of prominent Belfast Presbyterians interested in reforming Irish Parliament. They invited Tone and his friend Thomas Russell to Belfast where the group met on 14 October 1791. It was there that the Belfast Society of the United Irishmen was formed. According to Bardon; Tennant was a key leader of the Society in Ulster, and an advocate of violent revolution, while Jonathan Wright states that Tennant must be considered one of the highest-ranking members of the secret organisation in Ulster. It is unclear when he joined the Society, but as early as December 1792; Tennant was listed as one of twenty-one committee members tasked with building out the organisation. Other members of this committee included Henry Haslett and Samuel McTier. Both were founding members of the Society, unlike Tennant. However, according to Wolfe Tone, Tennant was a member of a pre-United Irishmen secret society in Belfast which included McTier and Haslett, as well as Samuel Neilson and Gilbert McIlveen.
Arrest and Imprisonment
During the rebellion of 1798, he was arrested for his membership of the United Irishmen, and imprisoned on a prison ship in Belfast Lough with William Steel Dickson, Robert Hunter and Robert Simms. On 25 March 1799, Tennant, Dickson, Hunter, and Simms joined the United Irish 'State Prisoners' on a ship bound or Fort George, Highland prison in Scotland. This group, which included Samuel Neilson, Arthur O'Connor, Thomas Russell, William James MacNeven, and Thomas Addis Emmet arrived in Scotland on 9 April 1799. Tennant would spend two years there. Unlike the more high-profile prisoners like O'Connor and MacNeven who would not be released until June 1802, Tennant, Dickson, and Simms were permitted to return to Belfast in January 1802 due to the pleas of his brother.
Later career
He was co-founder, in 1809, of the Commercial Bank, and he worked in the bank until it became Belfast Banking Co. in 1827. He was on the Board of the Spring Water Commissioners and the Belfast Banking Company, and was manager of the Belfast Academical Institution and Vice-President of the Chamber of Commerce. Tennent eventually became the town's richest merchant and banker.
Later life
In 1814, Tennant purchased the village and demesne of Tempo, County Fermanagh. He bequeathed property to the Presbyterian Church, and died of cholera at the age of 73. He left behind at last 13 illegitimate children, all of whom he recognised and supported.
