The only provinces yielding a considerable surplus were perhaps Sicily, where the Carthaginian system of taxation prevailed, and more especially Asia from the time that Gaius Gracchus, in order to provide for his largesses of corn, had carried out the confiscation of the soil and a general domanial taxation there.

According to manifold testimonies the finances of the Roman state were essentially dependent on the revenues of Asia.
The assertion sounds quite credible that the other provinces on an average cost nearly as much as they brought in; in fact those which required a considerable garrison, such as the two Spains, Transalpine Gaul, and Macedonia, probably often cost more than they yielded.

On the whole certainly the Roman treasury in ordinary times possessed a surplus, which enabled them amply to defray the expense of the buildings of the state and city, and to accumulate a reserve-fund; but even the figures appearing for these objects, when compared with the wide domain of the Roman rule, attest the small amount of the net proceeds of the Roman taxes.

In a certain sense therefore the old principle equally honourable and judicious-- that the political hegemony should not be treated as a privilege yielding profit--still governed the financial administration of the provinces as it had governed that of Rome in Italy.

What the Roman community levied from its transmarine subjects was, as a rule, re- expended for the military security of the transmarine possessions; and if these Roman imposts fell more heavily on those who paid them than the earlier taxation, in so far as they were in great part expended abroad, the substitution, on the other hand, of a single ruler and a centralized military administration for the many petty rulers and armies involved a very considerable financial saving.
It is true, however, that this principle of a previous better age came from the very first to be infringed and mutilated by the numerous exceptions which were allowed to prevail.