Trajan was a Roman emperor who ruled from 98 to 117 AD. He is best known for his military conquests, which expanded the Roman Empire to its greatest territorial extent. Under his leadership, the empire conquered regions such as Dacia (modern-day Romania) and parts of the Middle East. Trajan was also admired for his public works, including roads, bridges, and the famous Trajan's Market. In addition to his military achievements, Trajan was known for his effective governance and social welfare policies. He implemented programs to help the poor and improve the lives of Roman citizens. His reign is often considered a high point in Roman history, marked by prosperity and stability.