The reliquaries of two Eucharistic miracles which took place in 1230 and 1595 are held in Florence’s Church of Saint Ambrose. In the miracle of 1230, a distracted priest left several drops of consecrated wine in the chalice after Mass. The next day, returning to celebrate Mass in the same church, he found in the chalice drops of living Blood coagulated and incarnated. The Blood was immediately placed in a crystal cruet. The other Eucharistic miracle took place on Good Friday in 1595, when several fragments of the Host were miraculously unharmed in a church fire.
The first miracle took place on December 30, 1230. A priest named Uguccione, having finished celebrating Mass, did not realize that several drops of consecrated wine remained in the chalice and had turned into blood.
The historian, Giovanni Villani, gives a precise description: “A day later, taking up the chalice, he found living blood coagulated […] and this was shown to all the women of the monastery and to all the locals who were present, to the bishop, and to all the clergy. And then the Precious Blood was revealed to all the Florentines, who gathered with great devotion to see. He took the Precious Blood from the chalice and put the Sacred Species in a crystal cruet and again showed the people, with great reverence.”
Bishop Ardingo of Pavia ordered that the reliquary be brought to him. He kept the Precious Blood for several weeks before returning the miraculous Blood to the sisters of the monastery for safe-keeping near the Church of Saint Ambrose. Pope Boniface IX, in 1399, granted the same indulgence as the Portiuncula to those faithful who visited the Church of Saint Ambrose, and contributed to adorning the reliquary of the miracle.