St Francis of Assisi
Saint Francis of Assisi abandoned a life of luxury for a life devoted to Christianity after reportedly hearing the voice of God, who commanded him to rebuild the Christian church and live in poverty. He is the patron saint of animals and the environment.
Born Giovanni di Pietro di Bernardone but informally named as Francesco, St Francis was an Italian Catholic friar, a deacon and a preacher. He founded several holy orders and is one of the most venerated religious figures in history.
Information from Bibliography and Wikipedia.