Who was the monarch when the British Empire abolished slavery in 1833?

William IV was the monarch when Britain passed the Slavery Abolition Act in 1833. He had become king in 1830, succeeding his brother George IV, and remained on the throne until his death in 1837.

The act received royal assent on 28 August 1833 and came into force on 1 August 1834. It abolished slavery in most of the British Empire through compensated emancipation, with the government paying compensation to slave owners rather than to the people who had been enslaved.

A major qualification is that emancipation was not immediately complete in practice. Most enslaved people over age six were redesignated as “apprentices” and required to continue working for former owners. The apprenticeship system ended in stages between 1838 and 1840.

The act also excluded several territories, including areas under the East India Company and Ceylon, where slavery was addressed separately. Britain had already abolished its participation in the transatlantic slave trade in 1807, but the 1833 law targeted slavery itself across much of the empire.