ALIACCI, LEONE. — Greek theologian and scholar, b. at Chios in 1586, d. at Rome on 19 Jan. 1669; the surname appears with the variant spelling of Allacio, or Allazio, from the original Greek 'Αλλάτιος.
At the end of 1599 he entered the Greek College in Rome, where he studied classical languages, philosophy, and theology, without taking holy orders, though living as a celibate. In 1616 he earned a doctorate in medicine. After being appointed by Paul V as a Greek-language writer at the Vatican Library, Gregory XV entrusted him with the task of transporting the Palatine Library from Heidelberg to Rome, a gift from Maximilian of Bavaria. The Pope’s death deprived him of the well-deserved reward, and under his successor Urban VIII he even suffered harassment and unfounded accusations. Alexander VII appointed him first custodian of the Vatican Library in 1661.
His industry and erudition are attested by two hundred and thirty bundles, or volumes, in the Vallicelliana Library of Rome, containing not only manuscripts of his works—many of them unpublished—but also copies of Greek, Latin, and Italian codices. The sixty or so publications of A., besides editions of ancient texts, literary history, and various scholarly works, include writings on the controversies between the Churches of Rome and Byzantium, composed with the aim of mitigating divergences and emphasizing doctrinal and disciplinary concordances, in the spirit of the Council of Florence (1439). Among these should be noted: *De Ecclesiae occidentalis atque orientalis perpetua consentione* (Cologne 1648), a major work; *Graeciae orthodoxae scriptores* (Rome 1652–59); and *Concordantia nationum orientalium christianarum in fidei catholicae dogmate*, written in collaboration with Abramo Ecchellense (Rome 1655).
He also rendered notable service to Italian literature with the works: *Poeti antichi raccolti da codici manoscritti della biblioteca Vaticana e Barberina*, and *Drammaturgia divisa in sette indici* (Rome 1666).