Giovanni Colombini was a 14th-century Italian merchant from a prominent Sienese family who underwent a profound religious conversion. After being moved by the life of Mary of Egypt, he abandoned his prosperous lifestyle to serve the poor and the sick. He eventually distributed his wealth to establish hospitals and cloisters, leading him to live a life of extreme poverty alongside his companions. He is recognized as the founder of the Congregation of Jesuati, an order dedicated to prayer and charitable works.