In his time Richard Dadd (1817-1886) was more famous for his private life than for his work. In 1843 he murdered his father, supposedly on the instructions of the Egyptian goddess Osiris. He escaped to France, where he was arrested. The following year he was committed to London’s Bethlem Hospital, an asylum in which he was kept for 20 years before he was sent to the new hospital for the criminally insane at Broadmoor, where he spent the rest of his life. This watercolour was painted at Broadmoor and depicts an obscure episode form the life of Leonidas, King of Sparta in Greece, in the fifth century BC, as related in a poem by Richard Glover (1712-1785). The degree of detail in this watercolour is typical of Dadd’s work.