The first written contemporary records were kept by priests and contained accounts of religious ceremonies and festivals held throughout the year. Since these records were written down year by year they are sometimes referred to as annals and the priests who updated them every year were called annalists. They were in the form of short summaries and they were extremely valuable at later reconstruction of a factual history of Rome because they made references to declarations of war, victories, defeats, and treaties. This form of written account was later used in "Dark Age" and early medieval Britain in the form of The Welsh Annals and The Anglo Saxon Chronicle. The idea of recording the passage of events year by year also appealed to Tacitus, whose Annals is one of the most valuable records of First Century Roman history.