Diocletian (Gaius Aurelius Valerius Diocletianus) was Emperor of Rome from 284 to 305, brining in the system in which the Empire was split in half and ruled in two separate administrations. In that capacity, he was the Emperor from 284 to 286 and Emperor in the Eastern half of the Empire, the more important part, from 286 to 305.
There are definitely things not to like about Diocletian, but there are admirable things as well, chief among them being that he retired, something unusual for Roman Emperors, and went back to his villa to farm.
We've included him for that reason.
He famously stated, when being asked to return to power to resolve conflicts that had arisen follwoing his retirement:
If you could show the cabbage that I planted with my own hands to your emperor, he definitely wouldn't dare suggest that I replace the peace and happiness of this place with the storms of a never-satisfied greed.
If only more in power had those thoughts.