He was the son of Charles Forbes, a schoolmaster in the parish of Rayne, Aberdeenshire, and of Marjory Wright, and was born there in 1708, his baptism being recorded in the parochial register as having taken place on 4th May of that year. He must have been a studious youth, as he was sent to Marischal College, Aberdeen, in or about 1722, at the early age of fourteen, and graduated there as Master of Arts in 1726. He then proceeded to qualify himself for orders in the Scottish Episcopal Church, and coming to Edinburgh in June 1735, he was there ordained priest by Bishop Freebairn. In December of that year he became assistant to the Rev. William Law at Leith, and soon afterwards, at the request of the congregation, was appointed his colleague. At Leith, it may be said, he lived and laboured for the remainder of his life. Like most of the Episcopalians of that day, he was an ardent Jacobite, indeed one of the most ardent, and but for a timely interposition of the 'hated Hanoverian' government would not improbably have shared the fate of some of his brethren whose end he chronicles. In that case there would have been no _Lyon in Mourning_, and it is but fair to say that though _The Lyon_ can never be considered, and does not pretend to be, an impartial relation of the events with which it deals, our literature of the Rebellion of 1745 would have been greatly the poorer by its absence. Nay, it may even be said that, but for the continuous energy and single-eyed purpose of Bishop Forbes in this work, much of what is now known on this subject would never have come to light. On hearing of the advent of Prince Charles Edward in the West Highlands, Mr. Forbes, with two Episcopalian clergymen and some other gentlemen, started off with the intention of sharing his fortunes, but all were arrested on suspicion at St. Ninians, near Stirling, and imprisoned. He notes the fact in the Baptismal Register of his congregation, as follows: 'A great interruption has happened by my misfortune of being taken prisoner at St. Ninian's, in company with the Rev. Messrs. Thomas Drummond and John Willox, Mr. Stewart Carmichael and Mr. Robert Clark, and James Mackay and James Carmichael, servants, upon Saturday, the seventh day of September 1745, and confined in Stirling Castle till February 4th, 1746, and in Edinburgh Castle till May 29th of said year. We were seven in number, taken upon the seventh day of the week, the seventh day of the month, and the seventh month of the year, reckoning from March.'[1] An incident of the roping of these prisoners at their removal from Stirling to Edinburgh is narrated by the author.[2]