During Anglo-Saxon times, the majority of people who could read and write were monks. Some of these monks wrote histories of their times, and some, such as Bede, tried to write a history of former times as well, using knowledge passed down the ages, and books written by Roman historians centureis before.
Bede was really concerned to tell about the spread of Christianity. He lived in early Anglo-Saxon times. Somewhat later, a kind of diary emerged. It was a statement of events as they occurred year by year. This kind of diary is called a chronicle. We now call it the Anglo-Saxon Chronicle, and what it says provides us with much of what we know about the Anglo-Saxons.