The Seleucid Empire was a Hellenistic state that emerged after the death of Alexander the Great in 323 BCE. Founded by Seleucus I Nicator, one of Alexander's generals, it encompassed a vast territory that included parts of modern-day Turkey, Syria, Iraq, and Iran. The empire was known for its cultural blending of Greek and local traditions, which influenced art, architecture, and governance. At its height, the Seleucid Empire was one of the largest empires of the Hellenistic period, but it faced challenges such as internal strife and external threats from rival powers like the Parthians and Romans. The empire gradually declined, leading to its fragmentation and eventual conquest by other empires.