Islamic Science / Astronomy / 9th century"Moon phases"in "Comprehensive introduction to the principles of astrology" by Abu al-Rayhan Muhammad ibn Ahmad al-Biruni (973-1048). Original title is "Kitab al-tafhim li-awa'il ?ina'at al-tanjim".The text is written in question and answer format and deals with the sciences needed by the astrologer : geometry; arithmetic and number theory; and judicial astrology.Written circa 839; copied in January-February 1436.British Library; Or. 8349 (Qatar Digital Library).London; British Library.