As well as the time spent in Rome, he travelled in Italy with Bessarion spending the summer of 1462 at Viterbo, Cardinal Bessarion's favourite summer residence, and, when Bessarion left for Greece in the autumn of that year, Regiomontanus accompanied him as far as Venice. He left Rome on 5 July 1463 when Bessarion was appointed as papal legate to the Venetian Republic.
Pati na rin ang oras na ginugol sa Roma, siya manlalakbay sa Italya sa Bessarion paggastos ng tag-init ng 1462 at Viterbo, Cardinal Bessarion ng mga paboritong tag-araw na paninirahan, at, kapag Bessarion kaliwa para sa Greece sa taglagas ng na taon, Regiomontanus na siya makaabot Venice . He left Roma sa 5 Hulyo 1463 kapag Bessarion ay hinirang bilang papa sugo sa Benesiya Republic.