Althaea was the queen of Caylion.
Percy Jackson's Greek Heroes[]
When her son Meleager was born, the fates tied his life force to a piece of wood that she hid away. However years later when he killed her other son Toxeus and her brother Plexippus for assaulting Atalanta, she took the wood and burned it, killing her son.
The Trials of Apollo[]
The Tyrant's Tomb[]
Apollo mentions her when talking about her son to Hazel Levesque.