A City Protected by Water
The Romans chose York’s location partly because the rivers provided natural defensive barriers on two sides. A thousand years later the same principle was used to extend the city’s defences. Extensive man-made waterways were created around the city as further barriers against attack.
It began with the Norman Conquest; William I ordered water from the River Foss to be diverted to fill a moat around the castle at York (from about 1068). Damming the River Foss to supply water for the moat caused large-scale flooding. The flooded area became known as the King’s Fishpond and, though the water has long since gone, the area still retains the name ‘Foss Islands’.
Another great defensive project took place in the thirteenth century. In about 1215, a water-filled ditch was dug around the perimeter of the city, running the length of the walls on the sides not protected by the rivers.
The water-filled ditch was 50 feet wide and 10 feet deep and the moat around the castle around 30 feet wide and a similar depth. The scale of these lost features is difficult to imagine today but visible evidence of the ditch does still remain, along Nunnery Lane, Lord Mayor’s Walk and Jewbury. Click here for a satellite image on Google Maps.
Only at the south-east gate of the castle is there evidence of a drawbridge spanning the moat.
A regulation of 1584 instructed the perimeter ditches to be cut and cleaned to a width of 12 feet and a depth of 3 feet; evidence of their declining defensive importance. The moat around the castle remained until the later eighteenth century.
Throughout the Middle Ages, defence and control of the River Ouse was provided by two chains, which were hung across the river; one upstream from Ouse Bridge, between Barker Tower and Lendal Tower and one downstream, between Skeldergate Tower and Davy Tower. The chains are first mentioned in the Custodies of 1380 following the city’s introduction of a river ‘through toll’ in the mid-fourteenth century. In June 1553 the city instructed that the two chains be sold for the common profit of the city. Hence during the Civil War (1642 – 1651), Royalists blocked the Ouse between Skeldergate Tower and Davy Tower, not with a chain, but with boats mounted with canons.