The oldest and largest stronghold in the Rule Valley was undoubtedly Bedrule Castle built in the 13th century by the Comyns, another influential family, who entertained Edward I there during his Scottish visit in 1298. On the death of the Red Comyn at the hands of Robert the Bruce in 1306, all the Comyn's lands were forfeited. Before 1320, the castle had been added to the Douglas possessions.
Sir James soon installed a Turnbull as its occupant and members of that branch of the family remained there for many generations. The power of the Douglases eventually almost equalled that of royalty and, indeed, as one old historian remarked that "nae man was safe in the country, unless he was either a Douglas or a Douglas man." And, of course, the Turnbulls proved themselves to be good and reliable Douglas men!
Although Bedrule Castle, among other Scottish Border strongholds, was destroyed by the English in 1545 during their devastating raid, the Turnbulls continued in heritable possession until about the end of the 18th century. - R.E. Scott, I Saved The King - 1977
The Royal Commission on the Ancient and Historical Monuments of Scotland visited Bedrule Castle in 1967 and recorded the following:
This castle stood on a bluff jutting W from the rising ground on the right bank of Rule Water (598180), 200 yds. NW, of the parish church (RCAHMS 1956, No.27). Here may be seen the last vestiges of a castle of enceinte, but the enclosure is incomplete as cultivation has destroyed all trace of building NE of a "head dyke" which cuts across the NE side from NW to SE. South-west of the dyke grassy mounds and heaps of debris are evidence of vanished structures, but give no clue to their date.
From the air, however, these fragments are seen to be components of a castle with an oval enceinte measuring approximately 200 ft. from NW to SE by 130 ft. transversely; from the curtain or enclosing wall there project a gatehouse on the NW, a circular tower on the SE and two intermediate circular towers on the W and SW. It is probable that two more towers, corresponding to the last, existed NE of the "head dyke", in the cultivated area. The enclosure has been divided unequally in two by a cross-wall running NE from the circular tower on the SW; between this tower and its neighbour on the W there has been a building bounded on two sides by the curtain and the cross-wall, while in the SE angle formed by the cross-wall and the "head dyke" there has been a second building. The gatehouse is approached by an old road, still traceable on the ground, which winds uphill from the river on the W.
The arrangement outlined above would suggest a date in the late 13th century. Bedrule then belonged to the Comyns and in 1298 was visited by Edward I (Gough); in 1315-21, following the death of Sir John Comyn, it was granted by Robert I to Sir James of Douglas (Reg Magni Sig Reg Scot 1984). In the following century it belonged to the Turnbulls, with whom it remained throughout the Stewart reigns.
The course of the SW portion of the enclosing wall and the faint outline of a possible building within its south angle are the only determinate remains of Bedrule Castle. The approach road to the site is intermittent and not considered worthy of survey.
In 1837 the Archibald Craig, parish minister, wrote that: The only remains of the old castle of the Turnbulls of Bedrule are the foundations of several building, which occupy a considerable space of ground. They are situated on the right bank of the Rule, on an eminence, at a small distance (north) from the church. The dike which separates them from the ploughed land on the east, contains some hewn and ornamental stones, which, there is every reason to conclude formed a part of the ancient castle.
About a furlong to the north-west of the ruins, on the other side of the Rule, is a mound partly artificial and partly natural, called Fastcastle, and seems to have been an outwork to the main building. It is of considerable height and compass, and must have been once surrounded with water, and, as its name imports, must have been very strong. Though this mound is now in the parish of Cavers, it seems, from its vicinity to, and connection with, the Castle of Bedrule, to deserve a place in this account. - The New Statistical Account of Scotland: Roxburgh, Peebles, Selkirk - 1845