We can’t say when the first buildings were raised on the Ness of Brodgar site because we’ve not yet reached them.
The earliest excavated so far is Structure Five, which, dating to around 3300BC, was raised around the same time occupation began at the settlements of Skara Brae and Barnhouse. But at the Ness we have evidence of activity that pre-dates Five’s construction.
A small exploratory trench under Structure Fourteen’s north-western wall revealed sherds of an Early Neolithic carinated bowl in a charcoal-rich layer. Burnt bone associated with the bowl was radiocarbon dated to 3512-3425BC .
Although it is not clear whether the deposit relates to a building older than Fourteen’s predecessor, Structure Thirty-Six, it does confirm some sort of activity at least a century before Structure Five was raised. This falls within the period suggested for wooden dwellings in Orkney, with stone gradually adopted as a building material from c3300BC .
Were the earliest Ness buildings timber-built? That remains to be seen.
State of flux
What is beyond doubt is that the Ness of Brodgar complex, from its earliest days, was constantly changing. New buildings went up as the old came down or fell out of use.
The evidence from 18 years of excavation points to a site in a centuries-long state of flux. A place that never stood still or was ever really “finished” in any sense of the word.
These can be seen as elongated, or multiple units, of the single house form, seen for example in the earlier houses at Barnhouse and Skara Brae. Does this new departure in architecture also reflect the introduction/invention of the new ceramic tradition Grooved Ware in Orkney?
These new structures were themselves replaced, within a century or so, by the buildings visitors can see today – e.g. Structures One, Eight, Twelve and Fourteen – larger and more complex versions of their earlier predecessors.
And the changes kept coming, not least due to the structural problems inherent in erecting buildings on top of their predecessors’ remains.
The herald of change
In among these episodes of rebuilding we reach a point where it is clear that the importance of the piered buildings had waned and their significance eclipsed.
The herald of this change was Structure Ten.
Built around 2900BC, this new addition was another marked departure from the architecture had defined the complex for centuries.
At a basic level, its architecture mirrors the later house styles for instance at Skara Brae but on a truly monumental scale.
Structure Ten was built on top of at least two other buildings and partially on the rubble of Structure Eight’s southern end. By this time most of the piered buildings had been abandoned, although at least Structures One and Twelve remained in use.
These, however, both had (or were about to) undergone major remodelling.
Due to its shaky foundations, Structure Twelve suffered a collapse. Although considered important enough to rebuild, the haphazard nature of the work meant that the former jewel in the Ness’ crown was a shadow of its former self.
Structure One was also remodelled and reduced in size – but in this case subsidence does not appear to have been the catalyst for its transformation.
So what was happening?
It could be argued that where once groups of people gathered at the Ness, the construction of Structure Ten, with its tiny central chamber, was meant for a select few. Perhaps ancillary structures were still needed for whatever was going on in and around Ten.
Structure Twelve, for example, has produced evidence of cooking on an almost industrial scale.
The bigger picture
But looking at the overall picture it has been argued that the changes apparent at the Ness of Brodgar – and its eventual abandonment – were part of a societal shift that swept across Neolithic Orkney from 2900BC onwards.
It was around 2900BC that the Barnhouse settlement – 400 metres to the south-east of the Ness complex – appears to have been abandoned and a large, monumental building, Structure Eight, constructed on the site.
Anyone who has seen Barnhouse Structure Eight will immediately note the similarities between it and Structure Ten at the Ness.
Radiocarbon dates from the ditch surrounding the Stones of Stenness ditch have led to the suggestion that the stone circle was raised around 2900BC.
These dates, however, came from bone found in the bottom of the ditch and the suggestion is based on two assumptions:
- That the ditch was dug at the same time as the megaliths were raised.
- That this “construction preceded the first dated material by only a short amount” .
What the dates do tell us is that the ditch – or a section of it – had been dug and was in “use” around 2900BC. The stone circle, however, could have been standing for decades, or centuries, before the addition of the enclosing ditch.
However, the date is interesting when we consider the idea that the Stones of Stenness, its ditch and bank, were created to enclose and contain the remains of a large Structure Ten-like building.
These few examples suggest there was something afoot that was affecting more than just the Ness of Brodgar.
In 2017, following a detailed reanalysis of radiocarbon and luminescence dates from Orcadian Neolithic sites, a possible explanation was proposed.
The authors noted a pattern suggesting settlement disruption across Orkney from c2900BC which, they concluded, was linked to “local political tensions and social concerns”. 
It was proposed that Orcadian society was caught up in the unsustainable, and ultimately self-destructive, pursuit of prestige, social status and influence .
Central to this was the importance of claimed ancestral links and genealogical descent  which led to a scramble for social standing, that was manifested, in a highly visual way, through the construction of bigger and better monuments .
This not only saw “increasingly large and elaborate stalled cairns”  as different groups sought to outdo each other, but elements of Irish passage grave architecture (Maeshowe, for example), adopted by “ambitious and widely travelled” Orcadians, looking to “enhance their power by appropriating an exotic tradition” .
The result was a competitive and unstable society in which rivalries were played out as people invested “time and labour in monuments relating to deities, ancestors and origins that stretched well beyond the shores of Late Neolithic Orkney” .
This obsession with monumental construction is suggested to have pushed Neolithic Orcadian society to breaking point and eventual collapse.
As activity in the monumental landscape around the Ness of Brodgar escalated from c3125-2850BC, a decline was noted elsewhere in Orkney with a clear “lull in settlement intensity apparent in the 28th century BC” .
Although activity picked up again in the outlying areas in the 27th/26th centuries BC, there was no resurgence around the “Heart of Neolithic Orkney” . Instead, it seems the Stenness/Brodgar area of the Orkney Mainland “ceased to serve as a significant place of human dwelling.” 
Back at the Ness complex, a collapse in Structure Ten, c2800BC, necessitated a lower-quality rebuild.
The remodelled Ten, although still huge, was more domestic in nature – as were its remodelled neighbours Structures One and Twelve, which remained in use. People were still coming to the site as evident from the smaller, scrappier buildings (e.g. Structure Twenty-Six) erected among the remains.
End of an era
Structures One and Twelve were finally abandoned c2700BC but the situation regarding Ten is not clear. We know that midden material was still being dumped on the huge mound in Trench T from 2800-2500BC, suggesting activities were still taking place in and around Ten until it was abandoned, partially dismantled and buried in rubble and midden.
Although evidence suggests that some Neolithic activity continued on the site, the glory days of the Ness of Brodgar were over.
The deposition of the massive bone deposit around Structure Ten seems to commemorate its former status or celebrate a new order as implied by the Beaker sherd and barbed-and-tanged arrowhead placed over the bone deposit.
Although Bronze Age activity is found elsewhere on the isthmus, the site of the former Ness complex appears to have been avoided, other than acting as a source of building stone as the structures were robbed.
-  Card, N., Edmonds, M. and Mitchell, A. (2020) The story so far. In Card, N., Edmonds, M. and Mitchell, A. (eds) The Ness of Brodgar: As it Stands. The Orcadian: Kirkwall.
-  Bayliss, A., Marshall, P., Richards, C. and Whittle, A. (2017) Islands of History: The Late Neolithic timescape of Orkney. Antiquity, 91(359), pp. 1171–1188.
-  Richards, C. (ed) (2013) Building the Great Stone Circles of the North. Windgather Press, Oxford.
-  Schulting, R., Sheridan, A., Crozier, R. and Murphy, E. (2010) Revisiting Quanterness: new AMS dates and stable isotope data from an Orcadian chamber tomb. Proceedings of the Society of Antiquaries of Scotland 140, 1-50.