A record of several decades was found in the abbey. It is not assumed that it was written in the abbey. The current hypothesis is that the record was made in the court of Louis the Pious and continued during the reign of his son, Charles the Bald. Proposed authors are Prudential of Troyes, followed by Hincmar of Reims, who has been mentioned several times in this blog, such as here. The fact that the Annals (beginning with the year 830) end in 882 when Hincmar was forced to flee Reims (and died) in the face of a Viking invasion lends weight to this theory.
Although a mere 50 years of events, they are a primary source for happenings in the West Frankish territory and the time of King of West Francia, Charles the Bald. These Annales Bertiniani ("Annals of St. Bertin") are the source for yesterday's story of Pope Adrian II and his wife.
The Annals include papal letters and quotations from acts coming out of church councils. They deal largely with the relations (conflicts) between the Church and the Carolingians and with hostile actions from neighbors. They contain one of the earliest mentions of the Kievan Rus, men who accompanied emissaries from Constantinople. (Remember that the Rus were the source for the so-called Varangian Guard employed by Byzantine emperors.)
Situated as it was on the extreme northern edge of France, the Abbey was a target for invasions from the north. Scandinavian groups engaged in routine spring voyages for plunder. Abbeys and monasteries, known to be filled with unarmed men and donations, faced constant raids by these groups later called Vikings.
Other sources for the 9th century are the Annals of Xanten, the Annals of Fulda, and the Chronicle of Regino of Prüm, which overlaps Bertin and continues until 906. Regino is an interesting character, and we'll turn to him and his writings next.

