Commentary on Ptolemy's Four Books (Tetrabiblos)

"The Commentary on Ptolemy's Four Books" is a work by al-Battani on the astrological Tetrabiblos of Ptolemy; al-Qifti and Ibn Khallikan list it, and Ibn al-Nadim elsewhere counts al-Battani among the commentators of that book. ³

Casiri's catalogue shows that a copy was once in the Escorial library, described as "a commentary on Ptolemy's Quadripartitum on the judgements of the stars, with tables" by al-Battani. ¹ That manuscript was lost with others, as Derenbourg noted; Nallino could not find it when he was at the Escorial in October 1894, and no trace of it appeared when the Arabic manuscripts were checked again in September 1901. ¹ Nallino thinks al-Battani chiefly explained the mathematical principles of astrology in it. ¹

A Berlin manuscript has been ascribed to al-Battani as this commentary; Nallino translated the chapter headings recorded by Ahlwardt and matched them to the chapters of the Tetrabiblos. ^{4 5} He concluded that it holds only long excerpts from the Tetrabiblos with nothing of al-Battani's, perhaps taken by its compiler from a copy that also contained al-Battani's commentary — whence the ascription; nor does it contain the tables Casiri saw. ²

Ali ibn Ridwan did not know the commentary, stating he had never seen a gloss on the Tetrabiblos; Ibn Abi al-Rijal, however, says that "Mahomet son of Geber Albategni" agrees with Ptolemy in drawing judgements from the eclipses that fall in the years of planetary conjunctions. ²