Milecastle 33 (Shield on the Wall), Hadrian's Wall

Milecastle 33 (Shield on the Wall) on Wall Mile 33 of Hadrian's Wall is located just north of the B6318 Military Road. The remains of the milcastle are mostly visible as earthworks, but there are also exposed fragments of the gates and walls. It was a long-axis milecastle with distinctive Type II gateways.

There are thought to have been 80 milecastles on Hadrian’s Wall, located every Roman mile (1,000 paces) along the Wall, with two turrets (observation towers) spaced every third of a mile between them. The Milecastles were rectangular forts manned by small garrisons (probably 10-30 soldiers). The milecastles significance was much more than just their role in defending the Roman frontier. The milecastles had gateways in the north and south walls, often with towers on the north gate. They controlled passage through the Wall, supporting the checking of movement and levying taxes (customs) on goods and people. The milecastles also provided a visible symbol of Roman authority and imperial control. After Hadrian’s Wall was initially built (AD 122-8), larger forts (such as Housesteads) were added to the wall, providing bigger bases for fighting units, suggesting a shift in Roman strategy.

In the 1930s a numbering system was devised, with the Milecastles numbered east to west. Milecastle gateways are classified: Type I were grander, featuring large masonry, symmetrical internal/external piers, and were often wider than deep (attributed to Legio II Augusta), while Type II were more utilitarian, built with smaller stones, with piers only on the inside, and were found on the narrower milecastles (attributed to Legio XX Valeria Victrix).