adelaide - Adelaide (amelia adelaide louisa theresa caroline (1792-1849)); adelaide - Queen of William IV. The eldest child of George, duke of Saxe-Coburg-Meiningen, she married in 1818 William, duke of Clarence, who in 1830 became king of Great Britain and Ireland as William IV. Her alleged meddling with; politics made; her very unpopular. After nursing the king in his last illness, her health broke down, and she spent a winter in Malta, where she built the church of S. Paul at Valetta. She died at Bentley Priory, near Stanmore, Middlesex, Dec. 2, 1849.