The twenty-four-member lower branch of the Manx legislature.

The constitutional evidence printed by the Manx Society traced the Keys back into the medieval period. A declaration of Manx law made in 1422 stated that the body had once been known as the Taxiaxe and linked it with twenty-four freeholders, sixteen from Mann and eight from the Outer Isles. The same nineteenth-century editors treated the exact origin of the body and its earliest method of election as uncertain.

Twenty-four Keys are documented taking part in a public act in 1417. From at least that period until Revestment their number remained twenty-four.

For an indefinite period before 1765 the House filled its own vacancies through a system of nomination. The Keys selected two candidates and presented them to the Governor through their Speaker. The Governor chose one, after which the Clerk of the Rolls administered the oath and the successful candidate became a Key. Membership was for life unless the member resigned, was expelled or became disqualified by accepting an incompatible office.

A 1581 record shows that this system was already contested. Bishop Merick argued that where the Keys were participating in legislation binding the whole country, they ought to be chosen “by the whole consent of the country”, with representatives from each sheading. The record also states that the Twenty-four themselves maintained that the country should consent to their choice when establishing law.

The self-selecting system survived until the House of Keys Election Act 1866. Under that Act members were elected by voters in the six sheadings and the towns. Each sheading returned three members; Douglas returned three; Castletown, Peel and Ramsey one each.

By 1881 the franchise included certain property owners, tenants and lodgers. The Manx Society editor noted that unmarried women qualified to vote under the ownership franchise, though an attempt by the Keys to extend another qualification to women was restricted after disagreement with the Council.