Non-Ptolemean Cosmology and Time-reckoning in Early Medieval Times: the Liber Nemroth de astronomia (original) (raw)

The Liber Nemroth de astronomia is a Latin cosmological work centered on the measurement of time, whose scientific foundations owe nothing to the dominant Ptolemaic astronomy. After a description by Ch. Haskins in 1927 and a large article by St. Livesey and R. Rouse in 1980, the Liber Nemroth remained largely unnoticed until B. Obrist (1994, 2005, 2011) and D. Juste (2004) took a renewed interest in it, and a session of the 2016 Galway Computus’ Conference was devoted to it (Obrist, Juste, Draelants). After the discovery of new manuscript witnesses, a critical edition, translation (Draelants-Somers) and commentary, is now nearing completion. As a result, the identity, time and probable context of writing, as well as the doctrinal content of the dialogue between the master Nemroth and his disciple Ioanton can be more clearly identified. The talk will bring together convincing evidence on these subjects. The Liber Nemroth was circulated in the medieval West as early as the beginning of the 9th century. It can also be shown that the work implicitly claims the anteriority of Nemroth's "Chaldean" science over that of Ioanton (i.e. Ionitus the Greek), and that it is therefore possible to identify striking similarities with doctrines and motifs present in Syriac and Jewish cosmological works. After an overview of the latest discoveries, a range of special features can be exemplified, such as the specific vocabulary, the place of astrology and meteorology in relation to computus in the work, the measures of time since Creation and of celestial distances, the use of arithmetical progression and extrapolation from smaller to bigger, the links between Microcosm and Macrocosm, and some typical cosmological notions such as the Natural forces and the role of movers of the cosmic winds as “virtues”, the order of the planets and their nature, the role of the cosmic Dragon, the pivots of the years, and the “stratigraphy” of the cosmos.