FREDERIC OF HEILO: Dutch ecclesiastic; b. at Heilo (17 m. n.w. of Amsterdam), Holland, in the early part of the fifteenth century; d. near Haarlem (14 m. w. of Amsterdam) Oct. 11, 1455. It is uncertain whether he belonged to the monastery of St. Willibrord at Heilo, but he is described as a priest and oblate in the monastery of the Visitation near Haarlem, where his superior was John à Kempis, brother of the more famous Thomas. He also acted as confessor in the monastery at Warmond, possibly in the house of the Brethren of the Common Life. Later he resided at Leyden and in a nunnery at Bereswijk. According to a letter of his the nuns so embittered his life that, to regain peace of soul, he returned to his monastery. His writings are extant in two manuscripts, and comprise the following works: Epistola contra pluralitatem confessorum et de regimine sororum, proving that a nunnery should have but one confessor; an epistle of similar content advising that women should not be governed but should be instructed by men; a letter to a priest who had entered into a monastery governed by strict seclusion, warning him to beware of losing his spirituality through contact with the world. Apologia super resignatione regiminis sororum (ed. J. C. Pool, see below); epistle to a monk concerning his moral life; Tractatus de peregrinantibus contra peregrinantes, a polemic against the misuse of pilgrimages solely for the sake of indulgences (ed. Pool); and liber de fundatione domus regularium prope Haerlem, a chronicle extant only in fragments, but important on account of its information concerning the ecclesiastical and moral conditions of the times, especially the year of jubilee 1450 and Nicholas of Cusa,. In addition to these extant writings, the following works, now lost, are also mentioned: De inclusione religosorum, alterum de eadem materia; De dignitate sacerdotali; De doctrina peccati venialis et mortalis, sive contra nimis scrupulosos et de remediis; De officiis rectoris sive pastoris; De collectione mentis in se; De choreis; Contra sacerdotem lubricum sive consolatio super infamia fratris ; Contra detractores religiosorum ; De fonte qui ascendit de paradiso; De imagine et similitudine Dei; Carmina de sancta Basilia in Warmunda quiescente; De festivitatibus beatœ Mariœ virginis; Sermones de tempore et de sanctis, and Epistolare satis pulchrum. The standpoint of Frederic was ethical rather than mystical, although he was a faithful adherent of medieval theology with its semi-Pelagian tendency.