Wales was in ancient times divided into three parts nearly equal, consideration having been paid, in this division, more to the value than to the just quantity or proportion of territory. They were Venedotia, now called North Wales; Demetia, or South Wales, which in British is called Deheubarth, that is, the southern part; and Powys, the middle or eastern district. Roderic the Great, or Rhodri Mawr, who was king over all Wales, was the cause of this division. He had three sons, Mervin, Anarawt, and Cadell, amongst whom he partitioned the whole principality. Wales was divided into divisions because: