The article studies a little-known episode of an important stage in the history of the Republic of Venice - the formation of national church identity and the codification of the experience of state-confessional relations accumulated here over centuries. Two protagonists of this period - the Orthodox Metropolitan Gavriil Seviros and the Catholic monk Paolo Sarpi united in opposition to the Holy See and in an attempt to create an independent Venetian Church. Events had been developing against the background of a long confrontation between Venice and the Holy See, the so-called “War of the Interdict”, which began with the fact that Pope Paul V excommunicated the republic for its independent position in church matters. An unrealized project, which had as its model the Orthodox state and the Church, is a unique example of the assimilation of the Eastern tradition by one of the famous Western theologians - Paolo Sarpi. His cooperation with Metropolitan Gavriil in protecting the Greeks from the influence of Rome was clearly manifested during a trial of 1610, two documents of which are first published in Russian in the appendix to the article. Thanks to Gavriil’s authority, the See of the Metropolitan of Philadelphia became prestigious, his title as Patriarchal Exarch in Venice gave him access to the Doge’s palace, and his status as the head of the Orthodox of Dalmatia and the Ionian Islands was subsequently twice confirmed by the patriarchs of Constantinople.