Editing Coregency (section)

===Roman Empire===
{{Unreferenced section|date=July 2023}}

It was common during the [[Principate]] for a [[Roman emperor]] or ''[[Augustus (title)|Augustus]]'' to appoint ''[[Caesar (title)|Caesar]]'' as designated heir and junior co-emperor, in many cases adopting them as their son, who did not necessarily have to be biologically related to them. This was merely a tradition and not a formal office until the [[Tetrarchy]], which attempted to codify this arrangement, but quickly fell apart. It regained significance, including under [[Zeno (emperor)|Zeno]], as well as when [[Justin I]] had his nephew [[Justinian I|Justinian]] named co-emperor shortly before his own death, [[Constantine IV]] was also named co-emperor by his father [[Constans II]] and who himself had several other co-emperors, and the practice was common in the centuries to come up through the [[Palaiologos|Palaiologans.]]