The Annals of St Neots were written in Latin ca. 1120, but may well be copies of contemporary sources. The Annals mention the Raven Banner in connection with the battle of Cynwit in 878 AD:
In quo etiam acceperunt illud vexillum quod Reafan nominant. Dicunt enim quod tres sorores Hynguari et Hubbae, filiae videlicet Lodebrochi illud vexillum texuerunt, et totum paraverunt illud uno meridiano tempore. Dicunt etiam quod in omni bello, ubi praecederet idem signum, si victoriam adepturi essent, appareret in medio signi quasi corvus vivus volitans; si vero vincendi in futuro fuissent, penderet directe nihil movens. Et hoc saepe probatum est.
Stevenson 1904:138
A translation is given in Lukman:
It is said that three sisters of Hingwar and Habba, i.e. the daughters of Lodebroch, had woven that banner and got it ready during one single midday's time. Further it is said that if they were going to win a battle in which they followed that signum, there was to be seen, in the centre of the signum, a raven, gaily flapping its wings. But if they were going to be defeated, the raven drooped motionless. And this always proved true.
1958:141
The exact same text also appears in some copies of Asser's Life of King Alfred, originally written in Latin in 893, but this may have been a later addition, copied from the Annals or a common source.
Literature
Lukman, Niels C. "The Raven Banner and the Changing Ravens: A Viking Miracle from Carolingian Court Poetry to Saga and Arthurian Romance." Classica et Medievalia 19 (1958). 133–51.
Stevenson, William Henry (Ed.). Asser’s Life of King Alfred together with the Annals of Saint Neots. Clarendon: Oxford, 1904.
