This clan originates in the lands of Donside that had once lain in the northern Pictish kingdom, and its very name is held to derive from the Gaelic Forba, meaning a field, with the Pictish place-name suffix-ais. The earliest historical references is a charter of the reign of Alexander III who died in 1286, and this does not record the planting of a new family, but the confirmation of Duncan of Forbes' title to his lands. His descendents were raised to the peerage of 1445 when Sir Alexander Forbes married a grand-daughter of Robert III. But this was the very year in which the Gordons became earls of nearby Huntley, and thenceforth Clan Forbes were constantly menaced by their powerful and predatory neighbours.
They enjoyed a certain advantage through embracing the reformed faith while the house of Huntley remained Catholic, but this was complicated by the marriage of the 8th Lord Forbes to a daughter of the Earl of Huntley. Both of her sons renounced their worldly possessions and ended their days as Capuchin friars, leaving their Protestant half-brother to succeed as the 9th Lord Forbes. By the 17th century, Arthur, the 10th Lord (1581-1641), was described as a Chief much decayed., 'an naked life-renter of an small part and portion of his old estates and living of Forbes.'
It was during the Forty-Five that the name of Forbes shone with greatest lustre. There was Robert Forbes (1708-1775), Rector of the Episcopal church at Leith, who attempted to join the Jacobites but was intercepted and imprisoned in Strirling Castle. He was the son of a schoolmaster in Aberdeenshire of uncertain pedigree. Having failed to take an active part in the cause, he determined instead to be it's chronicler, and assembled the invaluable collection of eye-witness accounts which was published long after his death as The Lyon in Mourning. He met Flora MacDonald in Edinburgh after her release from captivity, and she was one of the many people who provided first-hand material. In 1762 he was appointed Episcopal Church Bishop of Caithness. Most distinguished of all was Duncan Forbes of Culloden (1685-1747), President of the Court of Session, a consistent opponent of Jacobitism. In the 1715 he and his brother raised a force for the government, but he protested to Sir Robert Walpole against the severe treatment of the rebels. He advocated the policy of raising Highland regiments, later adopted by Pitt, and when he was the sole remaining representative of the Hanoverian government in the north during the Forty-Five, he acted with sense and courage. After Culloden he attempted to restrain the bestialities of Butcher Cumberland.
The Chief of the clan Nigel, 23rd Lord Forbes (b. 1918), is the premier Baron of Scotland.