Diocletian was a Roman emperor who ruled from 284 to 305 AD. He is best known for his significant reforms that transformed the Roman Empire, including the establishment of the Tetrarchy, which divided the empire into four regions governed by co-emperors. This system aimed to improve administrative efficiency and address the challenges of governing a vast territory. Additionally, Diocletian is recognized for his economic reforms, including the introduction of a new currency and efforts to stabilize prices through the Edict on Maximum Prices. His reign marked a turning point in Roman history, setting the stage for the eventual rise of the Byzantine Empire.