St Francis (*1181 +1226)was the son of a prosperous cloth merchant in Assisi. When his father objected to having his goods sold without his consent to pay for the restoration of a church, the bishop commanded Francis to repay the money. He did. He also renounced his father and gave back everything he had ever been given, even his garments.
He began a life of perfect evangelical poverty, living by begging and even then only accepting the worst food that people had to give. He preached to all the love of God and the love of the created world; because, having renounced everything, he celebrated everything he received, or saw, or heard, as a gift. A rich man sold everything and joined him in living next to a leper colony; a canon from a neighbouring church gave up his position and joined them also. They looked into the Gospel and saw the story of the rich young man whom Jesus told to sell everything; they saw Jesus telling his disciples to take nothing with them on their journey; they saw Jesus saying that his followers must also carry his cross.
And on that basis they founded an order.Francis went to Rome himself and persuaded the Pope to sanction it, though it must have seemed at once impractical and subversive, to set thousands of holy men wandering penniless round the towns and villages of Europe.
Because Francis was wearing an old brown garment begged from a peasant, tied round the middle with string, that became the Franciscan habit. Ten years later 5,000 men were wearing it; a hundred years later Dante was buried in it because it was more glorious than cloth of gold.
There is too much to say about Francis to fit here. He tried to convert the Muslims, or at least to attain martyrdom in doing so. He started the practice of setting up a crib in church to celebrate the Nativity.
Francis died in 1226, having started a revolution. The Franciscans endure to this day.