Ubertinus. Ubertino of Casale, leader of the Spiritual Franciscans, who expressed extreme views regarding evangelical poverty. He was born in 1259, and died about 1330. Owing to his warm advocacy of the strictest ideas he was severely condemned by the authorities, and his history is a matter of considerable difficulty. His chief work is generally considered to be Arbor uitae crucifixae JESU Christi.