Diocletian was born in Dalmatia in 244 AD in a poor family. We don’t know much about his childhood life, but we do know that he joined the military and was very good at it, so that is how he became famous.
Diocletian was commander in the 270’s in Balkan peninsula. Then he acted as commanders guard in 283. Then when Numerian, the previous emperor, was killed Diocletian was the first choice as emperor.
So then Diocletian officially became emperor was in November 20, 284 AD. When Diocletian ruled he noticed that he couldn’t rule the whole kingdom himself, so he decided to divide the kingdom to East and West.
So he ruled the Eastern part of the Kingdom and another general, Maximian, to rule the Western part of the Kingdom.
In 305 Diocletian became ill, and he was the first emperor to retire from his throne. He retired to Dalmatia and lived another 3 years until he died.