Third of the children of Giovanni Paolo Giovanelli and Giulia Calbo, he was descended from a patrician family from Gandino,[1] near Bergamo, enriched thanks to the textile trade.

In the mid-17th century, the Giovanelli family accumulated wealth facilitated the diversification of family activities economically, with interests in copper mines in Slovakia and Hungary and large estates in Bergamo, Veneto, Trentino and Tyrol, while some of its members pursued careers in the military field at the service of the Emperor in the fights against the Turks, earning noble titles.

After Clement XIII died, he returned to Venice where the Senate elected him bishop of Chioggia on 15 April 1773,[3] appointment confirmed by the Pope on 12 July 1773,[4] after he had obtained on 24 May 1773 a doctorate in utroque iure at the University of Padua.

Called to swear allegiance to the new regime, he came accompanied by the clergy and, almost blind, had the parish priest of San Bartolomeo read a diplomatic declaration inviting the people to abide by the new laws while respecting religion.

After the Treaty of Campo Formio, by which Venice was dependent on Austrian monarchy, the Emperor Francis II appointed Federico Maria a secret advisor and Pope Pius VI, on the way to his captivity in France, an apostolic delegate.