Lorenzo de’ Medici was one of the embassy which the Florentine Signoria sent to congratulate the new Pope. The other ambassadors were Donato Acciaiuoli, Agnolo della Stufa, Bongianni Gianfigliazzi, Domenico Martelli, and Piero Minerbetti, the first of whom was spokesman. Martelli and Minerbetti were knighted in Rome. ‘In the month of September, 1471’ so we read in Lorenzo’s memoirs, ‘I was sent as ambassador to Rome on the occasion of the coronation of Pope Sixtus, and was received very honourably. I brought from thence the two marble busts of Augustus and Agrippa which the Pope presented to me; and besides a chalcedony vase, and many cameos and other things purchased by myself.’ The Pope’s affection and confidence were shown in various ways. The Roman Depository, _i.e._, the Receiver’s office, was handed over to the Medici, with the permission to choose as their representative Giovanni Tornabuoni, director of the Roman bank. New privileges were also granted to them in connection with their share in the farming of the alum-works of Tolfa. It was an important concession. In the days of Pope Pius II., Giovanni di Castro, son of the famous jurisconsult, Paolo, the principal co-operator in the revision of the Florentine statutes, (finished in 1415), discovered alum-deposits in the rock while making geological investigations in the hilly country between Civita Vecchia and the territory of Viterbo, in the vicinity of Tolfa. He instantly perceived the importance of his discovery, which promised to free the West, hitherto poor in this mineral, from a tribute to the distant East, made more inaccessible by the Turkish conquests. In fact, the produce soon amounted to 160,000 gold florins; and it is well known what sanguine hopes Pius II., whose eyes were directed towards the East, indulged, that this new source of revenue would aid his enterprises. Genoese houses had employed themselves with the alum-trade till the Medici concluded a contract with the Papal exchequer, which afterwards gave rise to many unpleasant misunderstandings with the financial department. However brilliant and cheerful things might look in Florence, and however bent the people seemed to be on enjoying the fruits of peace, warnings were not wanting that their security rested on a false foundation. In the year 1470 a sudden tumult, to which the exiles of 1466 were no strangers, had created momentary anxiety in the town of Prato, but order had been soon restored. A much more serious case was the rebellion which two years later took place at Volterra, as it not only was a source of misery for the town, but cast the first real shadow on the reputation of Lorenzo de’ Medici.