The resulting instability in the imperial office and the nearly-constant state of civil war and insurrection threatened to destroy the Roman Empire from within and left it vulnerable to attack from external adversaries.
[1] A barracks emperor could not boast of a distinguished family name or a successful career as a statesman or public servant.
To accommodate the vast demands of buying off their soldiers, the state often simply seized private property, which damaged the economy and drove up inflation.
Diocletian instituted a number of reforms designed to stabilize the empire and the imperial office, brought an end to the Crisis of the Third Century and inaugurated the Dominate era of Roman history.
They were military strongmen who effectually ruled the empire as imperial generalissimos controlling weak-willed puppet emperors, rather than taking the title themselves.