A tradition of natural science books continued in the middle ages from ancient Greek and Roman writings through the early middle ages, when writers such as Isidore of Seville (6th century) and Bede (early 8th century) write treatises on cosmology and calculation of time. Later expanded at Fleury and taken further still by Abbo of Fleury, who lived at Ramsey in the 10th century and was an important intellectual link to the continent, the tradition flourished in Britain's monasteries. To these natural science books belong a tradition of diagrams which incorporate Christian cosmological doctrine into classical theories on the structure of the heavens and earth, uniting geography, physics and computation of time to demonstrate the harmony of creation. Books such as this one (which is in two separate manuscript fragments in the British Library) would have been textbooks for training monks and churchmen. The diagram shows a figure labelled to the left 'Vita' (Life), standing above a figure labelled on his halo 'Mors' (Death): it was used for calculating the duration and outcome of illnesses. The sum of the numerical value of a patient's name plus the number of the lunar day of the illness's inception and the result divided by thirty. If the resulting number fell in the realm of Christ / life, recovery was indicated, if Satan / death, then fatality. This method was a 'band-aid' which served in place of real astrological prediction because of the lack of accurate astronomical instruments and tables.