St Francis of Assisi imitated Jesus Christ, his divine master, as closely as he could, abandoning his possessions for the benefit of the poor. His voluntary poverty was perceived as the recovery of an earlier strand in the Christian tradition, the belief that Christ and the Apostles had lived in simplicity and some physical hardship. As a symbol of this life of sacrifice the friars' badge of identity was the cord around their waist; they were known as the cordati. The cord's three knots signified the vows of poverty, chastity and obedience. As the movement spread, friars reached almost every diocese of Christendom; within a century of the founder's death there were 1,4,21 friaries, with the greater number to the north of the Alps.

Friars left their mark upon the medieval Church and society – their itinerant ministry took them to almost every parish. Their origins coincided with the growth and expansion of cities in western Europe. Their apostolate was attuned to the pastoral needs of the city and they became part of its fabric. They brought the Gospel to the laity in colourful, dramatic and intelligible terms, preaching in both church and piazza. This adaptation became a salient feature of their preaching and the allied ministry of hearing confessions. Friars preached peace in the divided cities of Italy, and friars restored peace and harmony, frequently in a public demonstration of reconciliation.