'Old men forget' or do they 'remember with advantages'? The problem of primary sources and objectivity

'Old men forget: yet all shall be forgot, But he’ll remember with advantages, What feats he did that day'.Shakespeare’s Henry V helped to create the myth of a Great King and has influenced histories of the Hundred Years War; the English remember Agincourt and their other victorious battles rather than the loss of the war. However Shakespeare’s was a history written nearly two centuries after the events it describes rather than a contemporary account. But Henry’s speech on memory contains a critical truth regarding primary sources that has received less attention. Whilst old men do sometimes forget, it is their tendency to remember their feats with advantages in their memoirs and diaries that is the focus of this article. If primary sources are not objective and contain distortions, omissions and errors, can the truth be uncovered in secondary sources that make use of them?