The mission to Florence took place in winter, or at least in a very cold month.

But the decisive argument is that Innocent III.

quitted Rome toward the end of May, 1209, and went to Viterbo, returning only to crown Otho, October 4th (Potthast, 3727-3803).

It is therefore absolutely necessary to postpone to the summer of 1210 the visit of the Penitents to the pope.

This is also the date which Wadding arrives at.
[2] 3 Soc., 35.
[3] 1 Cel., 32; 3 Soc., 51; Bon., 34.Cf._Test.