The invention of the arrowslit is attributed to Archimedes during the siege of Syracuse in 214–212 BC. Slits "of the height of a man and about a palm's width on the outside" allowed defenders to shoot bows and Scorpions from within the city walls. Although used in late Greek and Roman defences, arrowslits were not present in early Norman castles. They are only reintroduced to military architecture towards the end of the 12th century, with the castles of Dover and Framlingham in England, and Richard the Lionheart's Château Gaillard in France. In these early examples, arrowslits were positioned to protect sections of the castle wall, rather than all sides of the castle. In the 13th century, it became common for arrowslits to be placed all around a castle's defences.