The Keep stands upon rather the highest part of the enclosure. It is rectangular, 43 feet east and west, by 51 feet north and south, and stands upon the curtain, with which its west and south faces are continuous. As it does not quite cover the whole end of the ward, this is closed by a low curtain, 17 feet long and 3 feet thick, which extends from the keep to the north-west angle of the ward. The keep is composed of a basement and three floors, and is about 60 feet high. The parapet is gone. It has a plinth only on the two exterior faces, where the ground is low, and there are two sets-off which indicate the level of the second and upper floors. At the end of each face is a pilaster, 7 feet broad, and of 6 inches projection, and those adjacent meet and form a solid angle. These pilasters rose clear of the wall to form angle turrets, of which parts remain. From the upper set-off, on the north and south faces, rises an intermediate pilaster, 3 feet broad. The walls at the base are 10 feet thick, and, at the top, 6 feet. The basement is at present nearly filled up with earth and rubbish, concealing much of the east side. Part of the south-east angle fell in in 1792, and obscures the details of the main entrance.

The Basement is at present entered by a plain round-headed doorway of 4 feet 7 inches opening, in the north wall near its east end. This has a rebate for an inner door, but no groove for a portcullis. The outer jambs are broken away. It is pretty clear, from a comparison of its ring-stones with the original arches above, that this entrance is an insertion, probably of the time of James I. or Charles I. In the same side, near the doorway, is a very peculiar air-hole, formed of two loops, 2 feet apart, which converge to a single exterior loop. There are similar loops, of much later date, at Caernarvon. Possibly the basement was divided into two chambers, and one loop opened from each; but there is no trace of any partition. In the west wall there was probably another loop, now converted into a window of 2 feet opening, square topped, set in a bold splayed recess, evidently an insertion of a period when security was no longer the first consideration. The window opens in the line of the plinth, the set-off of which is carried over its head as a square hood-moulding. The south wall was blank, and so, probably, was that to the east. The basement was 13 feet or 14 feet high, with a flat timber ceiling. There certainly were no mural chambers, and no staircase in it. It was probably entered from above by a trapdoor and ladder, and used as a store.

The first floor, about 13 feet high, seems to have had loops in plain round-headed recesses in the north, south, and west sides, of which the latter is broken away, and a two-light Tudor window inserted. The northern loop has also been replaced by a similar window. In the south wall the loop is represented by a small square opening. In the ruins of the east side may be traced the remains of a doorway and the base of a lobby and staircase in the wall. It is clear that the external door was in this face, near the south end, and that it opened direct into the first floor, while right and left, in the thickness of the wall, was a mural passage, at its south end a mere lobby, but to the north containing a straight staircase which rises 13 feet by twelve steps, 4 feet 4 inches broad, towards the east angle, where was a small lobby which opened on the second floor, and was lighted by a loop in the east wall.

Thus, the second floor was entered in its east side by a direct mural stair, like those at Carlisle, at Chepstow, and at Ludlow. In each of the sides, north, south, and west, of this floor is an original round-headed recess, and in the east wall, over the mural stair, are traces of a shorter recess, placed higher up, whence seems to have been a passage into a mural chamber in the south-east angle. The southern recess alone contains its original window. This is a small coupled window of two lights, square headed, but within a round-headed arch. The dividing shaft is decidedly Norman, as is the whole character of the opening. The north window is also coupled and round headed, but looks like a Stuart insertion. The east and west windows are square headed, of Tudor date. In the north-west angle is a mural recess with loops, possibly a garderobe, and in the north-east angle a square-headed doorway opens by a lobby into a well-stair, which commences at this level and ascends to the roof. It is 7 feet 6 inches in diameter, and rises 31 feet by forty-six steps to the allure, or rampart walk. This second was originally the principal and uppermost floor, lofty, and with a high-pitched roof, the weather moulding of which is still seen on the east and west walls. The roof ridge was at the level of the rampart walk, and, as the north and south walls seem original, there must have been a deep cavity on either side, with the gutter in its bottom. Subsequently this roof was removed, and replaced by a flat roof, at the rampart level, the line of which is marked by a row of corbels in the north and south walls. The cause of this change, common, probably, to all Norman keeps, was the superior convenience for defence of a flat roof, rendered possible by the introduction of sheet lead as a roofing material.

The third floor was formed by dividing the height thus gained by a floor laid at the level of the springing of the old roof, and thus was created a second floor of 10 feet, and a third of 20 feet. In the west wall was opened a square-headed window, in a splayed recess, and close south of it is a small Tudor fireplace, the flue of which ascends into the south-west turret. The east wall is less perfect, but still shows the line of the old roof, and the jamb of a Tudor window. In the north-east angle is the door from the well-stair.

The floors of the walls were throughout of timber, the joists of the first and second resting in the holes in the north and south walls of the turrets; that at the south-west is probably modern. It contains the flues of several fireplaces which appear to have been inserted in the south wall, but which have fallen out. The keep probably had originally no fireplaces. The north-east turret contains the head of the well-stair. The other two turrets seem to have been mere shells, having only the two outer walls. They all rose about 12 feet above the rampart walk, and 5 feet or 6 feet above the crest of the parapet on the outside of the east and south walls of the keep. Near the top are ranges of triangular holes formed by thin tile-stones set on edge, and looking much like pigeon-holes, which they probably were. The row in the south wall has five holes, and in the south-east turret are three. In the east wall are two sets, one of three holes, and one, imperfect, of two. There is one hole in the north-east turret. They are evidently original, and do not appear to communicate with the interior. There is no trace of a regular forebuilding, for which the keep, like Goderich, was too small, but there was probably an open stair, either of wood or stone, ascending to the main door, which was about 12 feet from the ground. The exterior of the keep was quite plain, and of rather rude workmanship. The pilasters are of square stones, and the wall, in part of similar material, and in part of stones of irregular shape, laid as uncoursed rubble. There is no herring-bone work, and no visible trace of Roman material worked up.

The keep is evidently late Norman, and the walls are original, though much pulled about, and with many insertions of the Tudor and Stuart days. This is another example of the high-pitched roof, as at Richmond and Bridgenorth, the whole roof having been concealed by the walls.

Probably the founder of the castle built both the keep and the curtain wall on the lines of the present curtain, and cut the cross-ditch which isolates it from the rest of the Roman camp. The gatehouse and hall, and the south-east tower were probably alterations and additions of the Decorated period. The whole fortress was repaired by Countess Anne, whose hand may be traced throughout the structure. The keep has been split with gunpowder, probably by order of the Parliament, producing fissures in its north and south walls.

Robert de Veteriponte, or Vipont, the head of a great Westmoreland family, to which the armorial bearings of the Musgraves and Lowthers, the Blenkinsops and Hellbecks, show them to have paid early allegiance, is regarded as the founder of the castles of Brougham and Brough, at any rate in their Norman form. His immediate ancestor came over with Duke William of Normandy, and the family first planted themselves in the counties of Devon, Northampton, and York. Robert, the second or third in descent, flourished in the reigns of Henry II., Richard, John, and Henry III., dying in 1228, the twelfth of the latter sovereign. He filled many posts of military trust, was custos of many castles, and sheriff of many midland and northern counties. He was also a justice itinerant, and of the Common Pleas. In 1203 (4 John) he had a grant from the king of the Bailliewick of Westmoreland and the castles of Appleby and Burg, at first during pleasure, but afterwards in fee. Possibly the grant was connected with the fact that his mother, Maud, was a member of the great Westmoreland family of Morville, and probably a daughter of Hugh de Morville, one of Becket’s assassins. Robert’s wife, Idonea de Buisli, was heiress of the castle and Honour of Tickhill. He was a man of very great wealth and power, and likely to have taken steps to secure his Westmoreland barony against its northern neighbours. The grant mentions the castles of Appleby and Burgh; and Burgh, that is Brough, was sacked by William of Scotland in 1174. Probably, therefore, there already existed some kind of strongholds at those places, founded, it may be, by the English on the Roman stations. Moreover, the year 1204 is very late indeed for keeps of so decided a Norman type, and it is no doubt possible that De Meschines, or De Morville, the preceding lords of the fee, may have built both castles.[2]

John de Vipont, son and successor, died 25 Henry III., in debt to the king, who gave his estates in ward to the Prior of Carlisle, who neglected the castles. In his time the keep of Brough was out of repair, and the joists rotten. Lord John sided with the barons, and died of wounds received at Lewes. His daughter, and finally sole heiress, Isabel, was married to Roger de Clifford,—the Roger of the inscription over the gate of Brougham,—and who was killed in battle in Anglesea by the Welsh, in the reign of Edward I. Robert de Clifford, their son, lord of the Honour of Skipton, of Appleby, Brougham, and Brough, fell at Bannockburn. There were then two parks at Brough, a mill, and the demesne land. The castle ditches let for the herbage at 6s. 8d. per annum, and the constable had 40s.