The first ruler of the Ottoman Empire was Osman I, who reigned from approximately 1299 to 1326. He is often regarded as the founder of the empire, which would grow to become one of the largest and most influential empires in history. Under Osman I's leadership, the Ottomans began to expand their territory in northwestern Anatolia. His legacy continued through his descendants, as the empire further expanded into Europe, Asia, and Africa over the following centuries. The name "Ottoman" is derived from Osman’s name, reflecting his pivotal role in establishing and shaping this significant historical empire.