David ben Yom Tov ibn Bilia was a Portuguese Jewish philosopher who lived in the thirteenth and fourteenth centuries.
Ibn Bilia was the author of many works, the greater part of which, no longer in existence, are known only by quotations. Among them were: Me'or 'Enayim, a commentary on the Pentateuch, quoted by Caspi, Levi ben Gershon, and chiefly by the author's countryman Samuel Zarza, who often criticized Ibn Bilia's interpretations as being too mystical; and Yesodot ha-Maskil, published, with a French translation by S. Klein, in the collection Dibre Ḥakamim, Metz, 1849.
In the Yesodot Ibn Bilia propounded thirteen articles of belief in addition to those of Maimonides. These are:
These, together with the thirteen articles of Maimonides, make twenty-six, the numerical value of the Tetragrammaton.
Ibn Bilia also wrote Ẓiyyurim, an ethical work; Kilale ha-Higgayon, a work on logic, of which only a fragment has been preserved (Neubauer, "Cat. Bodl. Hebr. MSS." No. 2168); Ma'amar bi-Segullot 'Or ha-Naḥash, a treatise on the medicinal virtues of the skin of the serpent, translated from Johannes Paulinus' Latin translation "Salus Vitæ" (Munich, No. 228).
In the past some scholars, including the nineteenth century scholar Moritz Steinschneider, have identified Ibn Bilia with the David ben Yom Tov who was the father of the Catalan astronomer Jacob ben David ben Yom Tov Poel. That David wrote works including the Kelal Qatan ("Concise Summary"), a treatise on the medical applications of astrology. However the two are now believed to have been separate individuals.