The Choragic Monument of Thrasyllos is a memorial building erected in 320–319 BCE on the artificial scarp of the south face of the Acropolis of Athens to commemorate the choregos, Thrasyllos. It is built in the form of a small temple and fills the opening of a large, natural cave. It was modified in 271–270 BCE by Thrasykles the son of Thrasyllos, agonothetes in the Great Dionysia Games. Pausanias refers to the monument indirectly, providing us with the information that in the cave there existed a representation of Apollo and Artemis slaughtering the children of Niobe.