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. This diagram, which has no title, is probably unfinished. Twenty-two concentric circles divided into sixteenths, it has the months listed in each 'wedge', each given a different number, and numbers relating to lunar months. It probably has to do with computation of dates or relating dates to the lunar calendar. The circular form, which must have made it difficult to read as well as write, is typical of the diagrams in collections of treatises like this one, because it signified in this context macro- and microcosmic harmony.