The saint was born in Gubbio, Italy, was ordained a priest, and made a canon. Against his own wishes but upon the request of Pope Honorius II, he became the bishop of his native city in 1128. In this capacity he was a model of apostolic simplicity, pastoral zeal, and personal holiness. His aid is popularly invoked against evil spirits. To this day his body remains incorrupt.

The power St. Ubaldus possessed against evil spirits was evident. The Church moves in a spirit world--good angels are all about, while constant vigilance is exercised against Satan and his devils. The liturgy contains a considerable number of exorcisms and adjurations. Then there are a series of sacramentals directed against the power of evil spirits; for example, holy water, palms, candles. Hold these sacramentals in highest esteem.

http://www.catholicculture.org/culture/liturgicalyear/calendar/day.cfm?date=2014-05-16