Please explain Diocletian significance within the framework of Imperial Rome and provide an example.

Diocletian was Roman emperor from 284 to 305. He believed that the major problem of ruling a territory as large as the Roman Empire was its immense size. One of the first things Diocletian did was to split the empire into two parts. He chose a co-emperor, Maximan, his son-in-law. Maximan ruled in the west, from Rome; Diocletian ruled in the east, from Nicomedia. According to author Donald Wasson (cited below), Diocletian's most significant accomplishment was " the tetrarchy - an idea that preserved the empire in its present state, with two emperors, but allowed for a smooth transition should an emperor die or abdicate. The new proposal called for two Augusti - Diocletian in the east and Maximian in the west - and a Caesar to serve under each emperor. This 'Caesar' would then succeed the 'Augustus' should he die or resign." This system remained in place and was highly successful for over 100 years.