On the northern side of the Temple of Apollo is the Temple of Artemis. The foundation was laid in the 6th century BC and is thought by some archaeologists to pre-date the Apollo temple. It consisted of a room, or cella, with columns in the centre. It may once have celebrated both Apollo and Artemis.
Most of what you see now, including the marble portal, derives from the temple's rebuilding in the 4th century BC. In the remainder of the sanctuary are the barely visible remains of temples to Isis, Hecate and Latona, and the tomb of Hercules.