Saint Francis of Assisi is a Catholic religious figure known for leaving behind a life of wealth and luxury to live in poverty and simplicity. He founded the Order of the Fratrum Minorum (Order of the Little Brothers), a movement that emphasized poverty, service to others, and love for all living creatures. Francis had several experiences that shaped his conversion, including being taken prisoner in war and experiencing illness. He decided to leave behind his worldly possessions and family ties to live in poverty.