Seleucus I Nicator (c. 335 BC – 257 BC) (Greek: Σέλευκος Α΄ Νικάτωρ) was the Basileus of Isauria. He was the second youngest son of Perséas VIII,the last Emperor of the first Diadochian Empire. He ruled over the largest piece of the former Diadochian empire. Seleucus like his brothers and his uncle claimed the imperial title; but unlike his brothers and uncles he was in possession of the Diadochian ancient capital, Persepolis in addition to the whole of Mesopotamos, Isauria, Amnion, Phrygia, Cappadocia, Persis, Hyrcania, Bactria, Sogdiana, Arachosia.