in Antiquity, a wall begun by the Emperor Hadrian, on the northern boundaries of England, to prevent the incursions of the Picts and Scots. It was at first made only of turf strengthened with palisades, but the Emperor Severus, coming in person into Britain, built it of solid stone. This wall, part of which still remains, began at the entrance of the Solway Frith, in Cumberland, and running north-eastward, extended to the German Ocean.