The city of Florence gave to the world Saint John Gaulbert. Although he enjoyed the benefits of an early Christian education, his youthful heart was soon attracted to the vanities of the world. A painful incident was the means which God made use of, to open his eyes. Hugo, his only brother, had been murdered and St. John had resolved to avenge his death. On a certain Good Friday he met his enemy in a place where there was no escape for the latter. St. John drew his sword and would have killed his adversary on the spot, but the latter threw himself on his knees begging him by the passion of Jesus Christ to spare his life. St. John was touched at the words, embraced his enemy, entered a church and prayed with many tears for the pardon of his sins.

He now entered the Order of St. Benedict, in which he made such great progress in virtue that after the death of the Abbot, the monks wished to impose this dignity upon him, but the Saint absolutely refused to accept it. Sometime later, he left the monastery with one companion in quest of greater solitude. Having visited the hermitage of Camaldoli, he finally settled at Valle Ombrosa in Tuscany. Together with two hermits whom he found there, he and his companions built a small monastery, observing the primitive rule of St. Benedict. Thus was laid the foundation of the Order of Vallombrosa.

The humility of the saint was such that he would never be promoted, even to Minor Orders. His charity for the poor caused him to make a rule that no indigent person should be sent away without an alms. He founded several monasteries, reformed others, and succeeded in eradicating the vice of simony from the part of the country where he lived. He died on July 12, 1073, at about 80 years of age.