We hear nothing of Cosimo till the time when Pope John XXIII., on his eventful journey to the Council of Constance, halted in Florence. The relations between the republic and the Pope were to be traced from the time when the latter was all-powerful under his predecessor, Alexander V., as Cardinal Baldassar Cossa. When John XXIII. called upon the Florentines to send plenipotentiaries to Constance, and the counsellors were undecided, Filippo Corsini observed that they must not say ‘No’ to the Pope. He it was who had first originated the Council of Pisa, through which the way had been paved to the new assembly, and without his active assistance Florence would not have been able to resist King Ladislaus. The Pope had been already in connection with the Medici when he was legate of Bologna, and during his reign the money matters of the Curia were chiefly in the hands of Giovanni di Bicci. After John XXIII., yielding to King Sigismund’s urgency, had consented to the Council of Constance, in spite of his disinclination to a council on German soil, he was for a time in Florence, where he resided in the convent degli Angeli of the Camalduli. It was here that the Medici, with many respected citizens, visited him, and entered into negotiations with him. Here, too, he addressed to Bartolommeo Valori, in whom he had great confidence, upon his warning of the danger of holding this council in a foreign country, the remarkable words: ‘I own that this council is not to my advantage; but what can I do if my fate compels me to it?’[54] When the Pope set out for the Lake of Constance in the autumn of 1414, Cosimo de’ Medici was among his escort; not, as has been supposed, overrating the position as an aid to him in his own affairs, but simply to manage the money matters of the Holy See.