MAMACHI, TOMMASO MARIA. - Dominican theologian and historian, born on the island of Chios on 3 December 1713, died at Corneto Tarquinia (now Tarquinia, Viterbo) on 5 June 1792. A student and professor at the convent of S. Marco (Florence), he was appointed (1740) by Benedict XIV to the chair of philosophy at the Collegio Urbano of Propaganda Fide in Rome. In 1746 he was elected librarian and then, after three years (28 April 1749), theologian of the Casanatense Library for Italy. Pius VI appointed him secretary of the Sacred Congregation of the Index (1779) and in 1781 master of the Papal Palaces. He served as examiner of bishops and theologian to several cardinals.
Through his works, especially archaeological and historical—some of them polemical—Mamachi reveals not only great erudition but also a profound knowledge of Greek and Latin. A first review of all his writings, both published and unpublished, was compiled by A. Papillon (v. BIBLICA). His most important work, *Originum et antiquitatum christianarum libri XX*, of which only the first four volumes were published (Rome 1749–55), is highly erudite. Special mention must be made, particularly for Dominican diplomatic history, of the edition he edited in collaboration with the Dominicans F. Pollidori, V. Badetti, and E. D. Cristianopulo (members of the first Dominican historical society, which Mamachi had been placed in charge of), of the first volume of the *Annales Ordinis Praedicatorum* (Rome 1756), begun by A. Bremond, with notes and an appendix of documents; it covers only the period corresponding to the life of St. Dominic (1170–1221).
Other works include: *De animabus iustorum in sinu Abrahae ante Christi mortem, expertibus beatae visionis Dei libri duo* (Rome 1766) and *Del diritto libero della Chiesa di acquistare e di possedere beni temporali, si mobili che stabili, libri tre* (Venice 1766; Rome 1769–70).