Niobe

A mortal woman daughter of Tantalus and the wife of Amphion, boasted of her superiority to Leto because she had fourteen children, seven male and seven female, while Leto had only two (Apollo and Artemis).

Apollo killed her sons as they practiced athletics, with the last begging for his life (Apollo would have spared his life, but had already released the arrow), and Artemis killed her daughters. Apollo and Artemis used poisoned arrows to kill them. Amphion, at the sight of his dead sons, swore vengence against Apollo. A devastated Niobe fled to Mount Sipylus of Lydia in Asia Minor and turned into stone as she wept.