Gaius Aurelius Valerius Diocletianus, commonly known as Diocletian, was a Roman emperor who reigned from 284 to 305 AD. He is known for his significant reforms to the Roman government and military, as well as his persecution of Christians. Diocletian implemented the Tetrarchy system, dividing the Roman Empire into four administrative regions, each with its own ruler. This system aimed to improve governance and stability. Diocletian also initiated a series of economic and social reforms, including price controls and labor regulations. His reign marked a period of relative stability and prosperity for the Roman Empire, but his persecution of Christians was a dark chapter in his legacy.