 Buonaiuti claimed to be Catholic and to want to stay so "usque dum vivam" ("as long as I live"), as he wrote to the theology faculty of the University of Lausanne, which had offered him a chair in History of Christianity if he joined the Calvinist Church.Buonaiuti was an exact contemporary in Rome with Angelo Giuseppe Roncalli, who was elected to the papacy as John XXIII in 1958.According to Roncalli's biographer Peter Hebblethwaite the two men were initially close friends, and this connection may have played a part in the future pope's abrupt removal from a seminary post early in his career, as well as in the "Suspected of Modernism" entry which was made against Roncalli's name in his official record in the Vatican archives, something he would later refute by inserting, in his own hand "I, Pope John XXIII, have never been a Modernist".