Diocletian and Maximian meet in Milan on the five-year anniversary of their rule, either in late December 290 or January 291, to discuss their successes and failures.

The meeting is undertaken with a sense of solemn pageantry; the Emperors spend most of their time in public appearances.

It has been surmised by David Potter that the ceremonies were arranged to demonstrate Diocletian's continuing support for his faltering colleague.

(Potter, David S. The Roman Empire at Bay: AD 180–395.

New York: Routledge, 2005) A deputation from the Roman Senate meets with the Emperors, renewing that body's infrequent contact with the Imperial office.

The choice of Milan over Rome further snubs the capital's pride, but it is already a long established practice that Rome itself is only a ceremonial capital, as the actual seat of the Imperial administration is determined by the needs of defense.

Long before Diocletian, Gallienus (r. 253–68) had already chosen Milan as the seat of his headquarters.

If the panegyric detailing the ceremony implies that the true center of the Empire is not Rome, but where the Emperor sits ("...the capital of the Empire appeared to be there, where the two emperors met"), (Panegyrici Latini 11(3)12, qtd.

in Williams, 57.)

it simply echoes what had already been stated by the historian Herodian in the early third century: "Rome is where the emperor is".

During the meeting, decisions on matters of politics and war are probably made, but they are made in secret.

The Augusti will not meet again until 303.