Question

Why did the Diocletian decide to split the empire

Answer 1

The empire was spit because it was believed that this empire had become to large and complex for one ruler to handle. 

Answer 2

Diocletian was a Roman Emperor from 284 to 305, during his reign the Roman Empire was very vast, it covered Europe, North Africa and parts of Asia. Because of the size of the Empire, it was very hard to be ruled effectively and the creation of provinces made this harder.

Because of that, Diocletian decided to break the Roman Empire into two parts, one the Western Empire that had its capital in Rome and the Eastern Empire that had its capital in Byzantium. The Empire would have two Emperors that were in charge of each piece that would rule separately.