Why the name "Francis"

Why did the Pope choose the name Francis?

Pope Francis recalls that right after his election his friend Cardinal Hummes “hugged me” and said, ‘Don’t forget about the poor!’ …Right away, thinking of the poor, I thought of Francis of Assisi. He is also the man of peace. That is how the name came into my heart: Francis of Assisi….For me, he is the man of poverty, the man of peace, the man who loves and protects creation….He is the man who gives us this spirit of peace.”