From Delanceyplace:
St. Francis of Assisi (1182-1226 CE), perhaps the most revered of all the Christian saints outside of the apostles themselves, took the practice of poverty to a new extreme. This was especially striking at a time when generally only the well-born entered these orders of monks, and in a world where the blind were laughed at and the weak scorned.
Francis also pioneered a type of classless equality unknown in his era: “Living according to the pattern provided in the gospels … meant practicing poverty at its most radical, both for Francis and for the brothers — 'lesser brothers' (fratres minores), as they called themselves (thus the Order of Friars Minor), or (to use Francis's word) fraticelli — who began to gather around him. … Francis went much further [than those before him]. For him and for his young brotherhood, Francis intended corporate destitution. Again, he states this emphatically, not gently, in the beginning of his first Rule: 'The brothers shall appropriate nothing to themselves, neither a place nor anything; but as pilgrims and strangers in this world, serving God in poverty and humility, they shall with confidence go seeking alms.' For a Benedictine, or even a Cistercian, living in stable residences and worshipping, often, in grand churches, 'poverty' had a different meaning.
More here.