They asserted that it was unjust to permit these people, by merely changing their allegiance after defeat, to escape punishment for the outrages which they had committed against Italians and actually to profit by being vanquished.
This antipathy to the Slavs of the former Empire was in a measure transferred to the Serbs, who were naturally sympathetic with their kinsmen and who were also ambitious to build up a strong Slav state with a large territory and with commercial facilities on the Adriatic coast which would be ample to meet the trade needs of the interior.
While there may have been a certain fear for the national safety of Italy in having as a neighbor a Slav state with a large and virile population, extensive resources, and opportunity to become a naval power in the Mediterranean, the real cause of apprehension seemed to be that the new nation would become a commercial rival of Italy in the Adriatic and prevent her from securing the exclusive control of the trade which her people coveted and which the complete victory over Austria-Hungary appeared to assure to them.
The two principal ports having extensive facilities for shipping and rail-transportation to and from the Danubian provinces of the Dual Empire were Trieste and Fiume.

The other Dalmatian ports were small and without possibilities of extensive development, while the precipitous mountain barrier between the coast and the interior which rose almost from the water-line rendered railway construction from an engineering standpoint impracticable if not impossible.

It was apparent that, if Italy could obtain both the port of Trieste and the port of Fiume, the two available outlets for foreign trade to the territories lying north and east of the Adriatic Sea, she would have a substantial monopoly of the sea-borne commerce of the Dalmatian coast and its hinterland.

It was equally apparent that Italian possession of the two ports would place the new Slav state at a great disadvantage commercially, as the principal volume of its exports and imports would have to pass through a port in the hands of a trade rival which could, in case of controversy or in order to check competition, be closed to Slav ships and goods on this or that pretext, even if the new state found it practicable to maintain a merchant marine under an agreement granting it the use of the port.
In view of the new conditions which had thus arisen through the dissolution of the Austro-Hungarian Empire and the union of the Southern Slavs, the Italian delegates at Paris began a vigorous campaign to obtain sovereignty, or at least administrative control, over Fiume and the adjacent coasts and islands, it having been generally conceded that Trieste should be ceded to Italy.

The Italian demand for Fiume had become real instead of artificial.