In 1865 he founded the weekly L'Amico della religione, which ceased after the popular uprisings of Palermo in September 1866.

The following year he founded the bi-weekly La Sicilia Cattolica, which absorbed the previous one.

He devoted himself to the edition of the Greek and Arab diplomas, present in the Sicilian archives.

He was the first to be a lecturer in the School of paleography and historical criticism - as the Vatican School of diplomatic and archival paleography was then called - established by Pope Leo XIII, at the Vatican Secret Archive, with motu proprio of 19 May 1884.

In 1890, he was appointed by Pope Leo XIII as "first custodian" of the Vatican Apostolic Library.