philaster) (d. c.397. Writer of the famous treatise Liber de Haeresibus, which sought to refute 128 Christian and 28 Jewish heresies. It met a real contemporary need and was used by . Its weakness was to place side by side major heresies such as Arianism and minor aberrations such as astronomical speculation. Before writing this book Filaster traveled widely, preaching against Arianism and other heresies, and thereby ensuring personal acquaintance with heretics. Toward the end of his life he became bishop of Brescia in N Italy, and he was succeeded in that see by Gaudentius.