For centuries, Mathura and Varanasi remained at the center stage of development. Both these places reached near perfection in stone carving, while maintaining their own distinctive style. In the 3rd century B.C., the imperial court of Ashoka provided a great boost to the art of stone carving. The stupas and cave temples of this period are perhaps the earliest surviving stone structures. The red sandstone of Chunar has been lavishly used in the stone sculptures, which were found in excavations of the Mathura and Agra areas dating back to the Mauryan era.