So far, 12 phases have been assigned to describe the chronological complexity and development of the site at The Cairns, running from the later Neolithic period to the Medieval and post-medieval periods.
The following chronological site narrative is provisional. During an ongoing site excavation, elements of the chronology and phasing are always liable to modification and transformation until well after the completion of the field work. Nevertheless, the well-preserved, deeply stratified, and architectural complexity of the site allows a remarkably definitive but complicated sequence to be constructed.
Phase 1: Mid to late 4th millennium BC
Phase 1 relates to the Neolithic stage of activity at the site. A later Neolithic settlement lies around 25 metres to the north of the main excavation trench at The Cairns.
Phase 2: Early 1st millennium BC
Bronze Age/earliest Iron Age activity. A phase of activity preceding the broch and Middle Iron Age settlement.
Phase 3: At least as early as the 1st century BC to late second century AD/early 3rd century AD
This phase comprises the establishment of the substantial Middle Iron Age settlement on site. The phase includes the founding of the broch (Structure A), and its early occupation, as well as a set of contemporary village buildings (Structures O, J, N, S and probably P), (and probably many others unexcavated), a major ditched enclosure system, and other acts of landscaping around the settlement.
Phase 4: Earliest post-broch activity – around late 2nd/early 3rd century AD
Structure K was established at this time as a new built element of the site on the northern side of the settlement and it partly overlay the infilled remain s of the enclosure ditch. Structures Q and R nearby Str K also seem to have been established at this time. Structure C1 on the North side of the broch remains may also have been first established at this time.
Phase 5: From AD300
Phase 5 sees the establishment of a further stage of post-broch settlement from around AD300 onwards. A series of large rectangular and cellular buildings (the Structure B complex) were set up over the infilled remains of the broch on the western side of the broch ruins. Also, at this time, Structure K, now largely a roofless ruin, was used to provide some shelter and a platform for an important episode of metalworking.
Phase 6: Before later 5th to early 6th centuries AD
Sometime before the later 5th to early 6th centuries AD the remains of the old broch mound were once again revisited and an elaborate underground passageway or souterrain was constructed outside and inside the old entrance of the broch. The Str B complex also continued to be active in this phase, with modifications.
In Phase 7, the souterrain was closed. Elements of its roof were slighted, and parts of the passageway were filled in. Over the southern end of the souterrain, a new building, Structure H, was built. To the north and east of where the souterrain had lain, a series of revetment walls and flagged surfaces were built in the form of three roughly parallel tiers of linear kerb, enveloping the remains of the broch mound on the east.
Phase 8: 7th century AD
In Phase 8, Structure H was abandoned and apparently much of its stonework robbed out to create a new structure, E, nearby. Str E was a large building, dug deeply into the surviving remains of the broch wall on the east side and associated with a substantial bone midden that began to develop between AD605 and AD667. Meanwhile, archaeomagnetic dates indicate that the Str E hearth was last heated sometime between AD645 and AD795. At some point during Phase 8, the Structure B complex came to an end and the major hearth in B1 was last heated between AD510 and AD860, as indicated by archaeomagnetic dating.
Phase 9: Late Iron Age or Early Viking period
During the very late Iron Age/Pictish or Early Viking period there was renewed activity in Structure C, a building embedded into the north-east remains of the broch wall, originally dating several centuries earlier. Ephemeral hearths, pits and smaller walls (including Structure C2), yielded diagnostically Viking/Norse artefacts from deposits before and during the C14 date range of AD1022-1155.
Phase 10: Late medieval/post-medieval
Many centuries later, even than the Viking/Norse activity, the site offers evidence of the pre-improvement agricultural landscape. This is in the form of remains of ridge and furrow (or “rig and furrow”) agricultural beds. We have archaeomagnetically dated silt in the base of one of these furrows to between AD1690 and 1820. Finds from this furrow included 17th-18th Century AD Dutch pottery.
Phase 11: 19th/20th century
The neighbourhood of the site underwent “the improvements” in the Mid-19th century and we know from documentary sources that the modern field boundaries were established around the site in 1864.
We also include in this phase the first antiquarian awareness of the site, which occurred in 1902 and 1903. The antiquary Rev Alexander Goodfellow made interventions into the mound at The Cairns. Their trenches were small and relatively gentle in terms of their impact.
Much later, in the Mid-20th Century, the landowner discovered a deep void in the top of the mound, whilst working in the field, and that intervention was also archaeologically recognisable to us.
Phase 12: Early 21st century
The current project. While it remains rather rare for archaeologists to assign their own work to a distinctive phase within the chronological narrative, we have taken the view that our own work and impact is the latest form of “inhabitation” on site.
What we have been doing on site, just as in all archaeological excavations, results in permanent modification and transformation of the place, sometimes substantially and dramatically so. By placing our own activities in the phase narrative of the site, we recognise that we are part of the ongoing processes of history, not hermetically sealed and divorced from that flow of time and human agency.