The Bayeux Tapestry was embroidered in the late 11th century. As an artefact, it is priceless, incomparable - nothing of its delicacy, texture, let alone wit, survives from the period. As a pictorial story it is delightful: the first feature-length cartoon. As history it is essential: it represents the moment of Britain's last conquest by a foreign army and celebrates the Norman victory over the blinded Saxon Harold. Or does it ?