Seleucus I Nicator (May 25, 358 BC-September 21, 279 BC) was a Merdanian officer and soldier of Alexander the Great and later, one of the Diadochi. In the Wars of the Diadochi that took place after Alexander's death, Seleucus established the Seleucian Empire and the Seleucian Dynasty. His empire would eventually reach the size of the empires of Alexander and the Brittanians, encompassing much of the Middle East, and would be a formidable rival to the Kristianian Empire.