Mousa, Old Scatness and Jarlshof: the Zenith of Iron Age Shetland

Description

Mousa: HU 457 236

Old Scatness: HU 389 106

Jarlshof: HU 398 095

The Iron Age in Europe was a time of dramatic cultural change but is not directly represented on the World Heritage List.  Iron technology complemented bronze tools and weapons and society became proto-urban. Across Europe people built in timber, but in treeless areas of Scotland they developed their already established dry-stone skills in order to build double-skinned broch towers (400-200BC) which stood up to 13m high. The landscape of Northern and Western Scotland was dominated by them, with more than 100 being constructed in Shetland and similar numbers occurring in Orkney, the North of Scotland and the Western Isles.  Further south, forts and houses were built of timber with low chance of long-term survival. However, the brochs were a ready supply of dressed stone and, as early as the middle of the Iron Age, reusing the stone was an attractive proposition.

As the need or desire to build a tower passed, broch building was replaced with remarkable single skinned roundhouses which had diameters of up to 13m and incorporated a mezzanine floor (from 200BC on). This is clearly demonstrated in some of the few examples which survive, which boast a scarcement ledge, and at Scatness, even the lower portion of a staircase. In some ways the roundhouses are even more remarkable than the brochs, given the reduction in wall thickness.  There are far fewer surviving roundhouses than there are brochs, perhaps because these were not such solid constructions.

Towards the end of the Northern Iron Age, (also known as the “Pictish period”) smaller, corbelled wheelhouses replaced the larger and more timber-heavy roundhouses (from 500AD on).  Some smaller roundhouses were adapted and new wheelhouses were created.  Wheelhouses comprised a series of corbelled “cells” centred on a hearth, and therefore (in plan) resembling the spokes of a wheel and a central hub. The roof of the central space was significantly reduced by corbelling the cells in stone. The whole structure may have been completely corbelled. Alternatively, the roof would require only minimal quantities of wood. Very few of these less substantial wheelhouses survive today.

This sequence of construction events took place over a period of more than 1,000 years and demonstrates a commitment to and investment in one place against a background of limited and diminishing resources, environmental degradation and climate change.

The best examples of this architectural tradition occur in a discrete area of Shetland’s south mainland – Mousa Broch, the Old Scatness roundhouses and Jarlshof’s partially roofed wheelhouses. These are some of the most significant monuments of the period outside the Roman Empire.  The components have Outstanding Universal Value in their own right but complement each other telling and emphasising different parts of the wider story. They demonstrate a sophisticated society evolving, thriving and investing long-term under deteriorating environmental conditions.

Mousa is the best surviving Iron Age broch.  The word broch is derived from the Old Norse (borg) for a strong or fortified place. Brochs are massive, circular, double skinned drystone towers which enclose an internal area of between 7 and 15 metres. Mousa is a largely complete drystone round-tower, 13 metres tall, with walls 5m thick at the base.  The walls rise above first floor level as two concentric walls, tied together with stone slabs, and containing cells, chambers and a staircase leading to the wall-heads. Mousa’s outer walls have a distinctive inward batter and the whole is made from massive blocks of dressed stone. Two lines of stones protrude from the inner wall and may have helped to support structural timbers of one or two upper, mezzanine style, floors.

Old Scatness comprises an Iron Age village of drystone roundhouses built around a remodelled broch, packed densely within the earlier ditch surrounding the broch. They are not all exactly circular, one being “egg shaped” in order to maximise the available space. Three complete roundhouses have been excavated and still stand, whilst walls of at least two others have been glimpsed during excavation, but remain largely undisturbed. Roundhouse internal diameters exceed those of brochs – up to 13m, but have single skinned walls and a mezzanine upper floor. This upper floor was supported by stone piers, which also divided the interior into individual spaces. What had originated as free-standing piers were later extended to the walls, creating rooms.

Jarlshof is an impressive multiperiod site, spanning the Neolithic -17^th century AD. Its Iron Age levels include a remodelled broch and the remains of a roundhouse. Crucially however, it includes three exceptionally preserved wheelhouses, where the corbelled roofs of the cells still survive. Whilst the structures are smaller and the stones used are largely field and beach stone, corbelling the cells displays a high degree of skill and proficiency in stonework.

Justification of Outstanding Universal Value

The property has Outstanding Universal Value (OUV) as an expression of monumental Northern European Iron Age architecture against a background of social and environmental change. It spans a period of more than 1,000 years from 400BC.  The property stands as a proxy for European Iron Age social and architectural developments at a key period of change and transition from the prehistoric to the medieval world, outside the Roman Empire. They have not survived elsewhere since construction was usually in timber.

The three sites occur in a discrete geographical area, and each represents one exceptional, complementary component of a 1,000 year series of complex, sophisticated, drystone buildings, reflecting an evolution of profoundly different social structures. They demonstrate a triumph of human endeavour and ingenuity against a background of limited and diminishing resources, environmental degradation and climate change. They bear testament to continuity and investment in one place.

Reflecting local conditions, the sites are a response in stone to the social drivers seen elsewhere in wood, turf and earth. As such they can stand proxy for Iron Age development more widely, having the potential to enhance the value of contemporary sites across Scotland and Northern Europe.

Criterion (iii): The architectural sequence displayed at Mousa, Old Scatness and Jarlshof bears exceptional testimony to the development of society in Shetland for a period of over 1,000 years from 400BC. Brochs and succeeding structural types represent the high point of a distinctive North Atlantic dry-stone building tradition. The three components of the property demonstrate how the architecture developed over that period. The architecture and associated material culture illustrate the inventiveness of society in response to an environment which was becoming increasingly treeless, marginal and climatically challenging in an island world which is still today considered marginal.

Criterion (iv): The property illustrates social and architectural developments in the late prehistoric North Atlantic world, from brochs to proto-urban settlements. Mousa is the best expression of what can be understood about brochs. Old Scatness displays exceptionally preserved roundhouses following rigorous, scientific, archaeological excavation.  The best surviving wheelhouses are located at Jarlshof. Together the components represent the capacity of human endeavour in employing the available materials to create a distinctive style of settlement with limited external influence, moving towards a proto-urban society and economy, despite the challenging, essentially treeless, landscape and deteriorating insular environment.

Criterion (v): The sophisticated architecture of Mousa (broch), Old Scatness (roundhouses) and Jarlshof (wheelhouses) are the best examples of Iron Age architecture for a 1,000-year period in which Europe moved from being prehistoric to proto-urban. The confident architecture and its evolution, demonstrate the commitment of a flourishing society to one place, whilst adapting to the environment as it gradually changed.

The drystone architecture evolved as timber supplies diminished, and the climate deteriorated (seen in increased sand-blow) making agriculture more marginal, with soils amended to maintain fertility and dispose of waste. The loss of this society reduced the area to a subsistence economy.

Statements of authenticity and/or integrity

Authenticity
Although part of Old Scatness was removed during road building, the surviving Iron Age remains were pristine when excavated to the highest standards, between 1995-2006. Comparison with excavated evidence from Scatness and documentary research for Jarlshof and Mousa, suggests that the form and design of each component remains true to the original. The use of dry-stone walling as the key construction component is credibly expressed at all three sites.  Although 19^th century conservation probably used cement, none is visible.

The use of brochs is debated, but the roundhouses and wheelhouses are more clearly residential. Old Scatness and Jarlshof excavations have been fully published with archives and artefacts held in Lerwick and Edinburgh respectively. There is potential at each site for further research on this.

All three sites occur within a geographically discrete area. The coastal location and setting of the components convey a very strong sense of their original setting in the island world of Shetland.

The relationship of the sites to the open, treeless, windswept environment, as well as to the sea, is retained in the openness of the landscape today.

The reconstructions at Scatness are located away from the site, in an archaeologically sterile area.

Integrity
All the physical attributes required for OUV are within the boundaries of the property, although the elements themselves are not entirely intact. The three components cumulatively provide a unique insight into the North Atlantic world and its development over a millennium.

At all three sites, the architectural integrity of both above and below ground features is intact, other than consolidation to provide greater structural stability. Recent documentary work at Mousa and Jarlshof and the Scatness excavation, indicates that earlier repairs, carried out to the standards of the day, can be recognised.  All three sites have recently been digitally surveyed (in line with the Historic Environment Scotland “Scottish 10” project) including inaccessible internal spaces in Mousa. This provides a baseline for all future work.

Following excavation, Old Scatness needs stabilisation. Its conservation is currently in hand, taking a light touch and thoroughly documented approach.

Current land-use including airport runways and CAA regulations, and natural heritage designations, provide protections for the locations and settings of the components, in addition to scheduling designations and planning policy. A new Local Plan, currently in preparation by the Planning Department, Shetland Islands Council, will include a policy for World Heritage Sites.

Climate change threatens the sites. Jarlshof is protected by a seawall and all three sites are regularly monitored. There is an opportunity to apply the Climate Vulnerability Index (CVI) methodology recently used by Historic Environment Scotland at the Heart of Neolithic Orkney WHS to the Shetland sites.

Comparison with other similar properties

Scotland: There are approximately 500 broch sites in Scotland of which Dun Telve and Dun Troddan (NW Scotland) and Dun Carloway (Lewis) are amongst the best surviving. None match the completeness in height or circumference of Mousa.  Clickhimin (Shetland) was significantly altered prior to the 1960s excavations.

The Historic Environment Scotland Statement of Significance for Mousa (available online) summarises Mousa’s values – ‘Mousa Broch is of outstanding national importance as the best preserved and tallest of Scotland’s broch towers. Brochs are the only building type unique to Scotland.’ ‘Mousa is the best preserved of all brochs and popularly accepted as the archetype for the group.’  

The later social and architectural changes epitomised by Old Scatness and Jarlshof (Historic Environment Scotland Statement of Significance available online) are also seen at Gurness and Midhowe (Orkney).  Those at Gurness were moved and rebuilt in the 1930s. Importantly, neither those nor remains in Caithness and the Western Isles have the surviving monumentality and degree of completeness of either the Old Scatness roundhouses or the Jarlshof wheelhouses. 

All three sites occur in a discrete geographical area which demonstrates the resilience and determination of the community to live and invest in one place, despite the depletion of resources against a background of environmental change. Each site offers the potential for further research to explore the relationship of climate change to environmental and social change.

In the North Atlantic world, and more specifically Scotland, the property does not overlap thematically either with the Heart of Neolithic Orkney (criteria (i), (ii), (iii) and (iv)) or the mixed property of St Kilda (criteria (iii), (v), (viii), (ix) and (x)). Neolithic Orkney is separated from Iron Age Shetland by 2-3,000 years, although the earliest settlement at Jarlshof offers an interesting comparison. The archaeology of St Kilda dates predominantly to the historic period.

Europe: There is a gap on the World Heritage List from the European Iron Age – the period in which society lay the foundations for subsequent state formation. The Hallstatt and the Dacian forts both have an important Iron Age component but are not inscribed for this. There is an Iron Age component to some Roman forts but the focus is Roman civilisation, not “indigenous” Iron Age settlement.

Typologically the similarities of brochs to the Bronze Age nuraghi of Sardinia have been noted since the 19^th century. The World Heritage property of Su Nuraxi de Barumini (criteria (i), (iii) and (iv)) includes one of the best examples of these towers built of large drystone slabs. In reality, these are rather different types of construction in southern Europe, although also a response to building in the round in stone. They date rather earlier than the Northern Iron Age, belonging to the middle to late Bronze Age (c.1500-800BC).  The apparent visual similarity however is intriguing to visitors to both areas and means that the nomination of Mousa in particular is complementary to the story of Barumini.

Of similar date and potentially offering a more pertinent comparison in terms of illustrating the development of villages around drystone towers (talayots) is Talayotic Menorca (Balearic Islands, Spain) currently in the process of nomination to the World Heritage List under criteria (iii) and (iv).

The Hallstatt and the Dacian forts both have an important Iron Age component but are not inscribed for this.

Further Work: A detailed Comparative Analysis will consider both geographical and typological frameworks. The island context offers an important basis for comparison.

The property is situated within the Shetland UNESCO Global Geopark.