The monument comprises the remains of a tower-house, probably of later medieval date, surviving as the south-eastern corner of the structure, with a series of earthworks defending a steep-sided, rocky coastal promontory that projects into the North Sea.
The surviving ruins of the tower-house are L-shaped on plan, stand toward the eastern tip of the promontory and are close to the N-facing cliff edge. Earthworks immediately to the west, likely to be an augmented natural feature, are interpreted as the remains of the barmkin ditch that runs north-south, separating the eastern third of the promontory. To the east of the castle stands the house known as Old Slains Castle, which was built in the 1960s for the late Countess of Errol and incorporates what may be a late 19th- or early 20th-century cottage. An area of hard standing associated with this house runs almost to the foot of the tower and the track runs directly past the southern shoulder of the ruin and cuts across the barmkin ditch.
Further to the west, beyond the barmkin ditch, is a roughly level grassy area, bisected by the modern track. On the northern edge there are two inhabited cottages interspersed by a ruined 18th- or 19th- century cottage whose walls stand to approximately 1m in height. In the centre of this area stands a large, unoccupied modern bungalow named by the Ordnance Survey as Dixon's Cottage.
At the western or the landward end of the promontory is a deep gully cutting north-south across the neck of land. The eastern side of the gully appears to have been augmented by the creation of a substantial bank along the top. At the far north-western corner of the promontory is what appears to be a steep-sided mound with what may be an artificially levelled top.
The area to be scheduled is irregular on plan, to include the promontory and the surrounding cliffs, in which evidence for the castle's construction and use as well as any earlier remains may survive, as shown in red on the accompanying map. To allow for their maintenance, the footprints of 13 and 19 Old Castle, Old Slains Castle and Dixon's Cottage, the gardens and property boundaries of Old Slains Castle and 13 and 19 Old Castle, all septic tanks, all above-ground elements of utility poles, the upper 0.3m of the existing track and hard standings, and all post-and-wire fences are specifically excluded from the scheduled area.
The monument's cultural significance can be expressed as follows:
Surviving as a substantial fragment of the SE corner of Slains Castle, a 15th-century tower-house, the site is the dominant feature of the exposed seaward promontory it occupies. Earthworks defining what may have been the inner and outer wards can be traced. Slains was destroyed in 1594 on the orders of King James VI.
Despite the presence of the (post-medieval) village of Old Castle over much of the site, the archaeological investigations of 1991 and 2007 indicate that that the promontory as a whole still possesses high archaeological value. The site, which comprises the whole of the promontory, retains the potential to inform us about any earlier occupation, the date and nature of the castle's construction as well as offering information about the development of the post-medieval fishing village of Old Castle that was largely abandoned by the early 20th century.
Slains Castle is an example of a 15th-century square tower-house with associated earthworks forming inner and outer wards. Castles such as this reflect local power centres and recipients of royal patronage, such as Sir Gilbert Hay who received the lands of Slains as reward for his loyalty to King Robert I during the Scottish Wars of Independence. Additionally, they have the potential to enable us to understand the impact of feudalism, patterns of land tenure and the evolution of the local landscape.
Slains Castle and its surroundings have a long-standing association with the Hay family. The late Countess of Errol previously occupied an adjacent house known as Old Slains Castle, while the unoccupied building known as Dixon's Cottage remains in the ownership of the present earl's family.
The family's long association with the castle can be traced to the early 14th century when King Robert I rewarded the loyalty of Sir Gilbert Hay of Errol with the lands of Slains and the title of hereditary High Constable of Scotland. Throughout the 14th and 15th centuries, the Hay family prospered because of loyal service to the Scottish crown. In 1372, Sir Thomas Hay of Errol married Princess Elizabeth Stewart (daughter of King Robert II), while in 1453 King James II rewarded the loyalty of Sir William Hay in the war against the Douglas family with the titles of Earl of Errol and Lord of Slains. The surviving SE corner of Slains Castle probably belongs to the 15th century.
Slains Castle was destroyed in October 1594 on the orders of King James VI. Francis Hay, 9th Earl of Errol joined the rebellion of George Gordon, 6th Earl of Huntly, and it is possible that the king may have personally supervised the castle's destruction, part of a royal campaign to pacify the region that also included the slighting of Strathbogie Castle. The destruction of Slains can be traced back to Francis Hay's signing of the Treaty of the Spanish Blanks, a conspiracy discovered in 1592, where several (Roman Catholic) Scots Lords reputedly set their names to a blank treaty pledging support to Philip V of Spain and requested military aid. Following the discovery of the treaty, Errol was declared a rebel and a traitor but avoided capture and joined Huntly's uprising in 1593. Lord Errol fought at the Battle of Glenlivet where the rebel force defeated the Earl of Argyll's royalist army.
Following the destruction of Slains and the collapse of Huntly's rebellion, Errol fled to Denmark in 1595 but secretly returned to Scotland the following year and, having publicly renounced his Catholicism in 1597, regained James VI's favour. Errol chose to abandon Slains on grounds that the cost of rebuilding was too high and built the house known as New Slains about a mile to the north. New Slains remained in the Hay family's possession until 1913 when the 20th Earl of Errol sold the property.
Although Slains Castle was destroyed in 1594, the promontory was subsequently occupied by the community of Old Castle, a fishing village first recorded in the 18th century. In 1845, the New Statistical Account of Scotland noted Old Castle as one of only two villages in Slains parish with a total of 14 houses and 84 inhabitants. Largely abandoned in the early 20th century in favour of fishing communities elsewhere in Aberdeenshire, particularly Torry, a handful of 19th-century buildings still remain standing. As well as two ruinous cottages, the occupied houses at 13 and 19 Old Castle and the cottage incorporated into the 1960s dwelling of Old Slains Castle are also likely to date from the 19th century. In April 2007, an archaeological watching brief during the creation of a cable trench revealed significant areas of rubble, interpreted as debris from the demolition of the castle or the levelling of fishing cottages.
Slains Castle is of national importance because it has an inherent potential to inform us of the construction techniques, defences and domestic life of a medieval castle occupied between the 15th and 16th centuries. It may also shed light on the extent and nature of the feudalisation of Scotland, particularly the north-east of Scotland. Although destroyed in 1594, archaeological interventions in 1991 and 2007 have demonstrated the survival of archaeological remains. Records relating both directly and indirectly to the monument's history further enhance this potential.
RCAHMS record the monument as Old Slains Castle, Tower House, NK03SE 2. Aberdeenshire SMR records the monument as Old Slains Castle, Castles; Ditches; Gateways; Ramparts; Walls, NK03SE 0002.
MacGibbon D and Ross T 1887-92, CASTELLATED AND DOMESTIC ARCHITECTURE OF SCOTLAND, Edinburgh: D Douglas, Vol. 3, 249.
New Statistical Account of Scotland 1845, ABERDEENSHIRE, Edinburgh, Vol. 12, 593-4.
Sinclair J 1791, STATISTICAL ACCOUNT OF SCOTLAND: COUNTY OF ABERDEEN, Edinburgh: William Creech.
Pratt J B 1903, BUCHAN (4th ed.), Aberdeen, 29-30.
Shepherd I A G 2006, ABERDEENSHIRE, DONSIDE AND STRATHBOGIE, Edinburgh: RIAS, 210.
Smith A 1875, A NEW HISTORY OF ABERDEENSHIRE, Aberdeen: L Smith, Vol. 2, 1223-4.