In recognition of his achievements, he was appointed bishop on December 1, 1766 and consecrated titular archbishop of Tyre on December 7, 1766 by Cardinal Henry Benedict Stuart Duke of York and Titular bishop of Frascati; his co-consecrators were his nephew Stefano Evodio Assemani, Titular bishop of Apamea in Bithynia, and Nicholas-Xavier Santamarie, Titular bishop of Cyrene. He died in Rome on 13 January 1768. Part of his work was lost in his apartment during a fire on August 30, 1768.