Thus Sicily even from the Carthaginian period formed a closed customs-district, on the frontier of which a tax of 5 per cent on the value was levied from all imports or exports; thus on the frontiers of Asia there was levied in consequence of the Sempronian law( 10) a similar tax of 21 per cent; in like manner the province of Narbo, exclusively the domain of the Roman colony, was organized as a Roman customs- district This arrangement, besides its fiscal objects, may have been partly due to the commendable purpose of checking the confusion inevitably arising out of a variety of communal tolls by a uniform regulation of frontier-dues.

The levying of the customs, like that of the tenths, was without exception leased to middlemen.
Costs of Collection The ordinary burdens of Roman taxpayers were limited to these imposts; but we may not overlook the fact, that the expenses of collection were very considerable, and the contributors paid an amount disproportionately great as compared with what the Roman government received.

For, while the system of collecting taxes by middlemen, and especially by general lessees, is in itself the most expensive of all, in Rome effective competition was rendered extremely difficult in consequence of the slight extent to which the lettings were subdivided and the immense association of capital.
Requisitions To these ordinary burdens, however, fell to be added in the first place the requisitions which were made.

The costs of military administration were in law defrayed by the Roman community.
It provided the commandants of every province with the means of transport and all other requisites; it paid and provisioned the Roman soldiers in the province.

The provincial communities had to furnish merely shelter, wood, hay, and similar articles free of cost to the magistrates and soldiers; in fact the free towns were even ordinarily exempted from the winter quartering of the troops-- permanent camps were not yet known.