On 11 July 1818, Adelaide married Prince William, Duke of Clarence. It was a double wedding with William's younger brother, Prince Edward Augustus, Duke of Kent and Strathearn, and Princess Victoria of Saxe-Coburg-Saalfeld. When they married, William was second in line for the throne. He became first in line when his brother, Prince Frederick, Duke of York and Albany, died in 1827. William and Adelaide became King and Queen of the United Kingdom when William's older brother, king George IV died in 1830.