Rizziero was born in Muccia, in central Italy, into a wealthy family. It was during his university years, when he was studying at the University of Bologna, that he chanced upon an immense crowd that had assembled to hear the words of a preacher in the city's public square. Spellbound by the words of the unpretentious but impassioned speaker, Rizziero resolved then and there to follow him—St. Francis of Assisi—and to renounce the world.
As soon as he received the Franciscan habit, Rizziero seemed to take on the spirit of Francis: He was filled with love of God, zeal for souls and a deep desire to embrace poverty. Following in the footsteps of the Poor Man of Assisi, Rizziero himself became a successful preacher for a number of years before being appointed provincial of the Marches.
Rizziero was a man of virtue who practiced self-denial, but he suffered temptations that often made him despair of God's mercy. One day, tortured by the fear that God had rejected him, he resolved to visit Francis in Assisi to test his regard for him. Though ill, Francis was aware of the trials his Franciscan brother was suffering. He sent two friars to greet Rizziero warmly upon his arrival and to escort him to Francis' bedside.
Francis rose from his bed, embraced Rizziero, blessed him and assured him of his affection for him. He assured Rizziero that his temptation had "served very much to increase your merit; but in future you will be delivered from it." With those words, Rizziero's despair disappeared. Though Francis died a short while afterwards, Rizziero lived another 10 years, blessed the entire time with peace of mind.
He was beatified in 1836.