Note 404 — Chapter IV · THE SOURCES FOR THE PERIOD 1100–1250 A. D.

This is indicated in the following note appended to a Latin translation 399of Ptolemy’s Planisphere made by Hermann the Dalmatian in 1143: “Quem locum a Ptolomeo minus diligenter perspectum cum Albateni miratur et Alchoarismus, quorum hunc quidem ope nostra Latium habet, illius vero comodissima translatione Roberti mei industria Latine orationis thesaurum accumulat nos discutiendi veri in libro nostro de circulis rationem damus” (Ptolemaei opera omnia, Heiberg’s edit., vol. ii: Opera astronomica minora, 1907, p. clxxxvii). Some have sought to ascribe this Latin translation of the Planisphere to Rudolph of Bruges, a disciple of Hermann. Reasons why it cannot be the work of Rudolph are given by A. A. Björnbo in: Bibliotheca mathematica, 3rd series, vol. iv, Stockholm, 1903, pp. 130–133. See also Duhem, Système, vol. iii, 1915, p. 173. The note quoted above shows that a certain Robert (undoubtedly Robert of Chester—or, of Retines—whom we know to have been an associate of Hermann) had translated Al-Battānī’s Astronomy. See also Suter, Astron. Tafeln, 1914 (under Khwārizmī, Al-, in the Bibliography), p. xiii.