Xaos

Xaos was, according to legend, the oldest planet in "the galaxy". Some believed that all life began there. The Valley of the Gods was located on Xaos and was adorned with large statues of several gods. The Sixth Doctor, Peri Brown, Frobisher and Kane met Kaon there before heading out to do battle with the Skeletoids. (DWM: The Warrior's Story)