Constabilis was an Italian Benedictine abbot born around 1070 in Tresino to the noble Gentilcore family. After being placed under the care of Abbot Leo I at the age of seven, he became a monk at the abbey of La Trinità della Cava. He eventually rose to the position of coadjutor and later succeeded Peter of Pappacarbone as abbot in 1122. He is remembered as the founder of the town of Castellabate, having begun construction on the local castle during his leadership.