Aesica (with the modern name of Great Chesters) was a Roman fort, one and a half miles north of the small town of Haltwhistle in Northumberland. It was the ninth fort on Hadrian's Wall, between Vercovicium (Housesteads) to the east and Magnis (Carvoran) to the west. Its purpose was to guard the Caw Gap, where the Haltwhistle Burn crosses the Wall. The B6318 Military Road passes about half a mile to the south of the fort.
It is believed that the fort was completed in the year 128 AD. Unlike other wall forts that project beyond the Wall, all of Aesica is south of the Wall. The Wall at this point is narrow gauge, but stands next to foundations that were prepared for the broad wall. There was speculation as to why the foundations for the broad wall had not been used to support the wall at this point. In 1939 it was found that milecastle 43 had already been built in preparation for the broad wall, and it is thought that it was the presence of this milecastle that prevented the north wall of the fort being built on the original foundations. It appears that the milecastle was demolished once the fort had been completed. The east gate and east wall cannot now be traced. The fort was an oblong, measuring 355 feet (108 m) north to south by 419 feet (128 m) east to west, occupying a comparatively small area of 3 acres (12,000 m 2). The north-east corner of the fort is now occupied by farm buildings, built over the route of the Wall. The fort had only three main gates; south, east and west, with double portals with towers. At some time the west gate was completely blocked up. There were towers at each corner of the fort. The military way entered by the east gate and left by the west gate. A branch road from the Stanegate entered by the south gate. The Vallum passed some short distance south of the fort, and was crossed by a road leading from the south gate to the Stanegate. A vicus lay to the south and east of the fort, and several tombstones have been found there. The fort was supplied by water from a aqueduct, which wound six miles (10 km) from the head of the Haltwhistle Burn, north of the Wall.
The 2nd-century garrison was the Sixth Cohort of Nervians, followed by the Sixth Cohort of Raetians. The 3rd-century garrison was the Second Cohort of Asturians with a detachment of Raeti Gaeseti.
Excavations were carried out in 1894, during which the ramparts were cleared. The west tower of the south gate was found to contain a hoard of jewellery, which included an enamelled brooch shaped as a hare, a gilded bronze brooch described as a masterpiece of Celtic art, a silver collar with a pendant, a gold ring and a bronze ring with a Gnostic gem. During this excavation the headquarters building (principia) was partially uncovered, together with its vaulted underground strong room. A barrack block was also found to the south-west of the principia. In 1897 a bathhouse was discovered, 100 yards (91 m) to the south, east of the branch road to the Stanegate. It includes a dressing room, latrine, cold room with cold bath, dry-heat room, warm steamy room and hot steamy room.
Aesica shown within Northumberland OS grid reference NY703667 List of places: UK ”¢ England ”¢ Northumberland