Lord Protector or otherwise unable to rule. Notable cases in England are: and in Scotland: The Lord Protector of the Commonwealth of England, Scotland and Ireland was the title of the head of state during the Commonwealth (or, to monarchists, the Interregnum), following the first period when a Council of State held executive power. The title was held by Oliver Cromwell (December 1653 – September 1658) and subsequently his son and designated successor Richard Cromwell (September 1658 – May 1659) during what is now known as The Protectorate. The 1653 Instrument of Government (republican constitution) stated that— Oliver Cromwell, Captain-General of the
Scotland in the Middle Ages before he was overthrown by Máel Coluim, the son of Donnchad, who some months later defeated MacBeth's step-son and successor Lulach to become king Máel Coluim III (Malcolm III). It was Máel Coluim III, who acquired the nickname "Canmore" ("Cenn Mór", "Great Chief"), which he passed to his successors and who did most to create the Dunkeld dynasty that ruled Scotland for the following two centuries. Particularly important was his second marriage to the Anglo-Hungarian princess Margaret. This marriage, and raids on northern England, prompted William the Conqueror to invade and Máel Coluim submitted to his authority, opening up Scotland