Curiales were expected to procure funds for public building projects, temples, festivities, games, and local welfare systems.
In the course of the 4th and 5th centuries, membership in the curial class became financially ruinous to all but the most wealthy among them (who in many cases were able to purchase exemptions from their obligations), especially in the West, which was beset by settlements of tribes that disrupted the administration of the Empire and precipitated a decline in living standards by half from 400 to 600 A.D [citation needed].
The Emperor Julian tried to combat this development by increasing the size of curial councils, spreading the burden more evenly to make the position less costly.
In the course of the 5th century the governance of the cities fell into the hands more and more of an outside group of 'Notables' made up of persons who did not have to belong to the councils: senators, magnates, ex-military officers with estates, the richer former curiales, bishops, ex-imperial officials of higher standing and certain exempted professional classes.
The emergence of the post of decurion may be found in Rome's decision to allow office-holders in Latin colonies in Italy to become Roman citizens in an attempt to create loyalty in 125 BC.
Many decurions illegally left their positions in an attempt to seek relief from this burden; if caught, they would be subject to forfeiture of their property or even execution.