[goldstategop]

Well his idea of a tetrachy didn't last but what he started - the division of the Empire into two halves become an accomplished fact. The Western Empire was gone in two centuries but the Eastern Empire would endure a millenium.

(Denny Crane: "Sometimes you can only look for answers from God and failing that... and Fox News".)

[Spktyr]

Whether the Byzantine Empire was really the continuance of the original empire or if it was really just a successor state is something we can debate some other time. However, Diocletian bought the entire Empire about two centuries that it probably wouldn't have had. It gave the Eastern Empire enough time to consolidate and stabilize.

Some historians think that the entire Empire would have collapsed by 300 if he hadn't done what he did - having read some of the accounts of the era, I think they're absolutely right.