Seleucus I Nicator was a prominent general and one of the successors of Alexander the Great. After Alexander's death in 323 BCE, Seleucus established the Seleucid Empire, which spanned a vast territory from the Aegean Sea to the Indus River. He played a crucial role in the Wars of the Diadochi, fighting against other generals for control of the former empire. Seleucus is known for founding several cities, including Antioch, which became a major cultural and political center. His reign lasted from 312 BCE until his assassination in 281 BCE, and he is remembered for his military prowess and administrative skills in managing a diverse empire.