Marcus Ulpius Traianus was the Roman emperor who ruled from 98 to 117 AD. This distinguished ruler is known by different epithets in history. Some of the famous synonyms or titles associated with Marcus Ulpius Traianus are Trajan the Great, Optimus Princeps, and Trajanus. He was also referred to as Marcus Ulpius Traianus Trajan by historians to avoid confusion with other individuals who shared his name. Trajan the Great was awarded this title for his military campaigns that expanded the Roman Empire and made it one of the most significant in world history. His reign saw great prosperity and peace, and his achievements continue to fascinate scholars and historians over the centuries.