Video Orientation to the University of Pennsylvania Library's LJS 501, a bifolium from a 14th-century manuscript copied in England of the mid-13th-century Latin translation by Aegidius de Thebaldis (assisted by Petrus de Regio) of the Old Castilian translation of an 11th-century Arabic treatise on astrology. The text on the bifolium is from Book 5 and Book 6 of the work, which are in the section concerning nativities. The bifolium has been bound in reverse so that the leaf with the end of Book 5 and the beginning of Book 6 (and the historiated initial marking the division) are on the first leaf, followed by the originally earlier leaf containing material from Chapter 14 of Book 5. Two marginal section headings (f. 2r) in the same hand as the text; a few brief marginal annotations.

Written in England in approximately 1320.