She married William IV in a double wedding where William's brother Edward married Victoria of Saxe-Coburg-Saalfeld. Adelaide bore children, but none survived. William had surviving children - all illegitimate. Edward and Victoria's child Victoria became Queen when William IV died in 1837. Adelheid's Wikipedia article is here.

1818 Duchess of Clarence Adelheid von Sachsen-Meiningen by ? (location unknown to gogm) the lost gallery

1830 Adelaide of Saxe-Meiningen (1792-1849), by John Simpson (Royal Pavilion & Museums, Brighton and Hove; Brighton Museum and Art Gallery - Brighton and Hove, East Sussex, UK)
