Taking advantage of the Seleucids' preoccupation with the wars against a Celtic invasion of Asia Minor in the west, and the chaos of the Third Syrian War around 245 BC, Diodotus and Andragoras, the Seleucid satraps of Bactria and Parthia respectively, declared their remote provinces independent states. However, in around 238, the Parni, an Iranian tribe from the central Asian steppes under Arsaces, invaded Andragoras' domain, defeated and killed him, and took over the land. The Parni then became known as the Parthians taking their name from the Seleucid province that they had conquered.