During the Middle Ages, Dublin was surrounded by a wall enclosing less than a square mile. The first fortifications made of wood were erected by Ostmen, people of Norse-Gaels descent, during the 9th century. The defenses were extended, attacked and fortified with stone for hundreds of years until they outlived their purpose during the 18th century. There were seven gates into the city. This section of an Anglo-Saxon wall on Lamb Alley, probably built during the 12th century, was part of New Gate. Only a few wall remnants remain in Dublin.