We must forget that the earth is round, and that the stars are suns, and not lamps suspended from a crystal vault; we must forget the cosmogony of Laplace, and believe in the science of Saint Thomas, of Dante, and of those cosmographers of the Middle Age who teach the Creation in seven days and the foundation of kingdoms by the sons of Priam, after the destruction of Great Troy.

Such and such a historian or paleographer is powerless to make us understand the contemporaries of the Maid.

It is not knowledge he lacks, but ignorance--ignorance of modern warfare, of modern politics, of modern religion.
But when we have forgotten, as far as possible, all that has happened since the youth of Charles VII, in order to think like a clerk in exile at Poitiers, or a burgher at Orleans serving on the ramparts of his city, we must recover all our intellectual resources in order to embrace the entirety of events, and discover that sequence between cause and effect which escape the clerk or the burgher.

"I have contracted my horizon," says the Chatterton of Alfred de Vigny, when he explains how he is conscious of nothing that has happened since the days of the old Saxons.

But Chatterton wrote poems, pseudo chronicles, and not history.