In the half-century after the assassination of the last of the Severan emperors, Severus Alexander, in AD 235, Rome was to know at least twenty emperors and several other 'hopefuls' who laid claim to the Roman throne. The Empire's territorial and economic unity came under threat, and the army stationed in the various provinces had now become the main regulator of the Roman constitution.
The case of Maximinus Thrax (AD 235-238) is typical of the dominant political and military conditions of that time. Though but a simple soldier, Maximinus managed, thanks to his impressive military successes at the expense of the German tribes, to climb all the rungs of the ladder and seize the topmost office of the Empire.

The new 'Illyrian' dynasty did their best to deal with this crisis in all departments of the Empire. Their main concern was how to rein back enemy raids across the Empire's frontiers and how to reinforce the unity of the state. Despite their efforts to compromise with the Senate's position and not to meddle with its economic interests, their period of power was one rocked by continuous assassinations of emperors.