The oldest scientific manuscript in the National Library is NLW MS 735C, which contains various Latin texts on astronomy. The volume, written in Caroline minuscule, consists of two sections, the first (ff. 1-26) copied c. 1000, in the Limoges area of France, probably in the milieu of Adémar de Chabannes (989-1034), whilst the second (ff. 27-50), from a scriptorium in the same region, may be dated c. 1150.
The main text in the older part is the Latin translation by Germanicus (15 BC-19 AD) of the Greek Phaenomena by Aratus of Soli (c. 315-c. 240 BC), which describes the constellations. This is illustrated with a series of remarkable diagrams and coloured drawings reflecting the overlap between myth, astronomy and astrology at this period. The images include a picture of the author being instructed by his Muse (f. 11v), familiar symbols such as a bull for Taurus (f. 18v) and twins for Gemini (f. 17r), as well as a representation of five planets as heads in medallions (f. 21v). The constellations are also illustrated by two drawings of the Southern and Northern Hemispheres (ff. 3v-4r). Other texts include Cicero's Somnium Scipionis (the dream of Scipio), which, with the commentary on it by Macrobius (found here in incomplete form) was extremely influential in the Middle Ages. It gave rise to a number of literary works using the dream as framework, notably the French Roman de la Rose and Le Somme le roi, manuscript copies of which are also found in the Library's collections.
Little is known of the early history of this manuscript. It was rebound in the early seventeenth century, probably in a London workshop, perhaps by the person whose initials, 'T. M.', appear in the blind-tooled decoration. It is listed as no. 11 in a catalogue of the library of Plas Power, Denbighshire, compiled in 1816 by Richard Llwyd, whose note 'Astronomy and very curious' can be seen inside the front cover of the manuscript. It may well have reached Plas Power much earlier, however, for it could be one of 'three or four old manuscripts' referred to in the catalogue made in 1778, and may well have been in the possession of the Welsh lexicographer Thomas Lloyd (c. 1673-1734), who lived out his last years at Plas Power. The volume remained there until 1913, when it was bought by the National Library.