Meanwhile a monk dressed in the habit of the Augustinian canons was riding down from the ridge and heading for Caen. This was Geoffrey of Maldon, an eminent professor of theology who had been brought on campaign by Edward to provide him with advice on matters of theology and ecclesiastical law that might crop up. His mission this day was to carry Edward’s offer of surrender terms to the defenders of Caen.
Given that the English were now embarked on a grand chevauchée, the terms were fairly generous. If Caen surrendered immediately the main English army would not enter the city, no looting would be allowed and the entire population could keep their personal possessions and lives intact. Of course, if the city did not surrender it would be looted and burned.
The monk was barely halfway through reading out the message to Bertrand and d’Eu when it was snatched from his hands by the Bishop of Bayeux. The Bishop, a relative of Bertrand’s who had been involved in the old feud with Harcourt, tore up the message and ordered Geoffrey to be thrown into prison. This was a serious breach of military etiquette and against all the customs of chivalry. The Acta Bellicosa records Edward’s reaction when his messenger failed to return “This wicked action of the French meant that their own punishment was all the more severe.”
It was not until late in the evening that Edward finally realised that Geoffrey of Maldon was not coming back, and by then it was too late to take any action. So it was at dawn on 26 July that the English marched down the ridge from Cheux towards Caen. Scouts were sent out ahead to discover the lay of the land and the French dispositions.
from "The Battle of Crecy, A Campaign in Context" by Rupert Matthews