Blockhouse known as the Cow Tower


Heritage Category: Scheduled Monument

List Entry Number: 1014780

Date first listed: 09-Oct-1981

Date of most recent amendment: 07-Aug-1996


Ordnance survey map of Blockhouse known as the Cow Tower
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The building or site itself may lie within the boundary of more than one authority.

County: Norfolk

District: Norwich (District Authority)

National Park: THE BROADS

National Grid Reference: TG 23961 09191


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

Blockhouses are defensive structures of widely varying design built specifically to house a small artillery garrison and to protect the gunners and ammunition from attack. Usually stone built, each structure was designed and built to protect a particular feature or area; typically they were located to command a river, harbour entrance or anchorage. The main components of blockhouses were a tower and bastions or gun platforms, although in some cases only the tower or the bastion was present. The earliest known blockhouse dates to 1398, but the majority were built in the first half of the 16th century by Henry VIII. Distributed along the east, south and south west coasts, there are 27 examples which are known to survive in various states of repair, mostly now destroyed or incorporated into later military constructions. Surviving examples will illustrate the development of military defensive structures and of tactics and strategy during this period of rapid change following the introduction of firearms. They will also preserve something of the life and experience of the common soldier who was required to live and work within them. All examples with substantial archaeological remains are considered to be of national importance and will be worthy of protection.

Cow Tower is believed to be one of the earliest blockhouses to have been built and is an impressive example of the use of brick in the medieval period. Its construction is also very well documented, with records of materials, workmen and days worked as well as expenditure. The walls of the building itself survive with very little alteration and retain a variety of features relating to its original occupation and use, and limited excavations during work to consolidate the standing structure have demonstrated that archaeological information concerning its construction is preserved below the ground surface. If, as the documentary record suggests, the site was occupied by an earlier tower, buried features relating to this are also likely to survive. The tower, which was intended to protect a vulnerable point on the river boundary on the west side of the medieval city, has additional interest as one of several surviving elements of the city defences.


Legacy Record - This information may be included in the List Entry Details.


The monument includes the medieval structure known as Cow Tower, which stands in isolation on the south bank of the River Wensum, commanding the angle of the river opposite the steep rise of St James' Hill. The site is at the north east corner of what was at one time a low lying meadow known as Cowholme, within the precinct of St Giles' hospital (now the Great Hospital), which was founded in 1249 by Bishop Suffield. The tower is not mentioned in the surviving account rolls of the Hospital but, according to the 18th century historian Blomefield, `the Great Tower called the Dungeon' was conveyed by the Master of the Hospital to the city of Norwich in 1378, in the same year that the bailiffs of the city were commissioned by the king to repair the city defences. The tower in its present form was built towards the end of the 14th century, and its construction is exceptionally well documented in the Treasurer's accounts for the year 1398-89, with several possible earlier references in records between 1386 and 1395. There are further documentary references relating to its maintenance and repair during the 15th century.

The walls of the tower, which is of three storeys, are built with a core of mortared flint rubble, faced internally and externally with brick, with external stone dressings. Around the base on the exterior face are three to four courses of squared, knapped flint with galetting (flint chips set in mortar) above a moulded stone plinth on a footing faced with alternating courses of flint and brick. A sequence of putlogs (sockets to support the horizontal members of timber scaffolding) is visible on the inner and outer faces of the wall. The internal floors and roof no longer survive, but the walls stand in part to almost their full original height at a maximum of 14.6m above the present ground level. The tower is circular in plan, with a projecting half-round turret containing a newel (spiral) stair on the south west side. The external diameter of the main body of the tower is c.11.5m at the base of the plinth and c.11m immediately above it, tapering to c.10.35m at battlement level, with the stair turret, which has an external diameter of c.3.9m north west-south east, projecting c.2m beyond. The wall thickness ranges from c.1.9m at ground floor level to c.1.35m at the top.

The entrance to the ground floor, which is at the level of the top of the plinth, c.0.35m above present external ground surface, is on the west side, adjacent to the stair turret, and comprises an external door opening with pointed arch and chamfered stone surround, a small, brick vaulted lobby contained within the thickness of the wall, and an inner door opening with jambs and pointed arch of chamfered brick. On the right (south) side of the lobby is the arched door opening to another small lobby at the foot of the stair turret. The turret, which has an internal diameter of up to c.2.7m, partly within the thickness of the wall, is lit at different levels by four small, internally splayed window openings, three on the south west side and another, the topmost, facing south east. The stair within, which gave access to the upper floors and battlements and is said to have been complete in 1809, still survives to first floor level and is constructed with brick treads around a newel post of limestone. The landings off the stair and arched door openings to the tower remain intact at first and second floor level.

The ground floor, which was probably vaulted above, is lit by a single, internally splayed, arched window on the south side and includes a broad fireplace on the north west side, adjacent to the entrance. Evidence for the vaulting includes a series of six large, arched sockets, some with angled bases, spaced at different heights around the walls, with diagonal chases in the brickwork outlining triangular arches of varying width above and between the sockets. It is thought that the sockets supported timbers which formed the ribs of the outer pitch of the vault, and that the chases were constructed to take the wall arches of the vault. The timbers would have supported a brick infill. A central column will have been required to carry the radiating inner ribs of such a vault, and although no trace of this survives above the floor level, it is possible that evidence for it survives below ground. Three other small recesses in the wall are thought to be niches to hold lamps.

On the first floor the wall is pierced by seven internally splayed openings set within recesses with splayed arches. Five of the openings are set with cruciform loops in stone, in a sixth the loop is missing, and the seventh, to the north of the door opening on to the stair turret, is a small arched window. On the east side is a door opening to a narrower, tunnel arched recess containing a garderobe (latrine) with a smaller loop in the wall behind. The setting for the seat of the garderobe remains largely intact, above a rectangular chute lined with brick in the thickness of the wall, and there is a lamp niche in the north wall alongside.

The floor level of the storey above is marked by an offset in the wall, with rectangular sockets for three north-south joists immediately below. Above this there are seven recessed openings, arranged in similar fashion to those on the first floor, but more closely spaced. As on the first floor, the opening to the north of the door to the stair turret has the character of a small window; the remainder were probably furnished originally with cruciform loops in stone, although only two, on the north east and south east side, retain these features. On the north side there is a second garderobe, very similar to the one already described, and on the south side, a fireplace, smaller than that on the ground floor. In the wall above these features are the remains of a brick string course which runs below the sockets for south west-north east joists to support a timber roof below the battlements.

The upper part of the battlements is unevenly eroded, but the nine wide, internally splayed rectangular embrasures in the parapet survive largely intact.

Cow Tower has been identified as an early form of artillery tower or blockhouse, intended to house guns and a garrison of gunners to defend the approach across the river. The cruciform loops on the first and second floor would have been used for firing small guns, and larger guns could have been mounted on the roof platform, to fire through the embrasures in the parapet.

The paved surface and railings on the river bank immediately to the north and north east of the tower and the piles which retain the bank are excluded from the scheduling, although the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

Legacy System number: 21412

Legacy System: RSM


Books and journals
Ayers, B S, Smith, R, Tillyard, M, 'Med Archaeol' in The Cow Tower, Norwich: A Detailed Survey And Reinterpretion, , Vol. 32, (1988), 164-207
Saunders, A D, 'Med Archaeol' in The Cow Tower, Norwich: An East Anglian Bastille?, , Vol. 29, (1985), 109-119
Smith, T P, 'Med Archaeol' in The Cow Tower, Norwich: The Chases...: An Alternative View, , Vol. 32, (1988), 199-202

End of official listing