Thomas Leland (1722-1785) was born in Dublin. Ordained to ministry in the Church of Ireland, his works include History of Philip, King of Macedon (1758), History of Ireland (1773), and a posthumous collection of sermons (1788). His only work of fiction, Longsword, Earl of Salisbury, was published in 1762. It was adapted for stage in 1765 as The Countess of Salisbury by fellow Dubliner Hall Hartson. The play remained popular into the early nineteenth century.
More on Thomas Leland can be found in various issues of The Green Book