Traditionally linked to the idea of a Dalmatian nation advocated by
Niccolò Tommaseo in the first half of the 19th century and regarded as a meeting of the Latin world with the Slavic world, initially the party also attracted the sympathies of several Slavic Dalmatians, while maintaining an undisputed open to the Italian cultural world. The Dalmatian branch of the
People's Party (, ), which supported the unification of Dalmatia with the
Kingdom of Croatia-Slavonia in Hungary, viewed the Autonomists as supportive of an Italian annexation of Dalmatia, which later on would have been indeed the ambition of the Italian state. The Autonomist Party received the vote of the
Dalmatian Italians and a number of bilingual Slavs, both Croats and Serbs, and controlled most Dalmatian coastal cities: this party had a majority in the
Parliament of Dalmatia in the mid-19th century. However, in 1870 democratic alterations to the electoral laws allowed the majority
Croatian population of Dalmatia to influence the elections for the first time. The democratic reforms allowed for a greater part of the general population to vote (but even areas where non-Slav population was the majority were affected) and so the Autonomist Party no longer had a majority: by the outbreak of World War I, only the city of Zara (now called
Zadar) remained in Autonomist hands. A similar but independent political development occurred in
Fiume, where
Michele Maylender, claiming greater autonomy from the centralizing Hungarian executive of
Dezső Bánffy, founded the (Fiume) Autonomist Party in 1896. Although the reference with Dalmatia was never made explicit among Fiume autonomists (who widely read Tommaseo and Bajamonti) the goals of the Party were very similar to that in Dalmatia as it opposed the inclusion of the city to Croatia. As in Zara the party remained in power up to 1914, and both cities, although claimed by the
Kingdom of Serbs, Croats and Slovenes at the
Paris Peace Conference, were finally assigned to Italy: Zara by the
Treaty of Rapallo and Fiume with the
Treaty of Rome, which gave Fiume to Italy and the adjacent port of
Sušak to Yugoslavia.
Antonio Bajamonti, the most prominent Autonomist in the history of the party, once remarked: Count Francesco Borelli Dalmatian deputy, argued for the autonomy of the Kingdom of Dalmatia, claiming that it had no connection whatsoever with Croatia. Though he admitted that the majority of the population was
Slavic in language, mentality and outlook, he claimed that Dalmatia's "higher" culture was Italian. At the beginning of the 20th century the Autonomist Party, having lost his majority in nearly all Dalmatia, started to be dominated by a group of Dalmatian Italians from Zara, led by Luigi Ziliotto and Giovanni Bugatto, who supported
Italian irredentism in Dalmatia: the party was suppressed in 1915 when Italy declared war on Austria during
World War I. ==Diet of Dalmatia elections==