BEDE ON CHRONOLOGY: Bede's two chronological works - De temporibus (On Times) and De temporum ratione (On the Reckoning of Time) were concerned with establishing the dates of Easter. Along with his histories, these still affect our style of dating: when equating the number of the year with the year of Jesus Christ's life, Bede invented the use of A.D., 'The Year Of Our Lord'. In stark contrast to 'dark age' cliches, Bede also knew the world was round, the moon affected tides and appreciated observational science. Several of Bede's works written prior to the History deal with chronology. These works have a significant influence on Bede's development as a historian. The Liber de Temporibus, written in 703, and the de Temporae Ratione, written in 725, both conclude with a chronicle of the six ages of the world.
De Temporae Ratione reflects the chronological theories Bede developed within the actual text of the work. In this treatise, Bede provided a detailed explanation of counting on the fingers up to one million. This was the basis for further theories on the division of time from the smallest units to the largest, which culminated in a discussion of problems with calculating time in terms of lunar and solar years.
At the end of the treatise, he included a chronicle of the different ages of the world. Like Saint Augustine and Isidore of Seville, Bede believed that time could be divided into six ages represented by the Creation, the Flood, Abraham, David, the Captivity of Judah, and the Birth of Christ. Most chronologists agreed that the first five ages had lasted for 5,500 years. Bede, however, was not content to accept the work of others and, using Jerome's Latin translation of the Hebrew Bible, proceeded to make his own calculations. He came to the conclusion that the first five ages had lasted only 3, 952 years, which had the effect of denying that Christ was incarnated during the sixth age. To Bede's horror, he was charged with heresy.
De Temporae Ratione is important for understanding Bede's development as a historian. His diligence in making his own calculations is an indication of his preference for primary sources, as opposed to second and third accounts. The chronicle of the sixth age found in this work also shows that Bede was already beginning to collect information for his History. It was an enlarged version of the chronicle in Liber de Temporibus, and "came to enjoy great popularity and frequently copied as an independent work [which] contain[ed] several references to events in the history of the English in Britain."