The Union of the Crowns (March 1603) was the accession of James VI, King of Scots, to the throne of England, and the consequential unification of Scotland and England under one monarch. The Union of Crowns followed the death of James' unmarried and childless first cousin twice removed, Queen Elizabeth I of England—the last monarch of the Tudor dynasty. The Union was a personal or dynastic union, with the Crowns remaining both distinct and separate—despite James's best efforts to create a new "imperial" throne of "Great Britain". England and Scotland continued to be sovereign states, despite sharing a monarch, until the Acts of Union in 1707 during the reign of the last Stuart monarch, Queen Anne.
From 1601, in the last years of Elizabeth I's life, certain English politicians, notably her chief minister Sir Robert Cecil, maintained a secret correspondence with JamesVI in order to prepare in advance for a smooth succession. Cecil advised James not to press the matter of the succession upon the queen but simply to treat her with kindness and respect. In March 1603, with the queen clearly dying, Cecil sent James a draft proclamation of his accession to the English throne. Strategic fortresses were put on alert, and London placed under guard. Elizabeth died in the early hours of 24 March. Within eight hours, James was proclaimed king in London, the news received without protest or disturbance.