This changed in the Middle Bronze Age, with a decline in monument construction, the expansion of livestock and arable farming, and a pronounced increase in the number of settlements, which by this stage consisted of much more substantial roundhouses.

Cornwall was an important source for tin and gold in the Bronze Age, and is the most likely provenance for these metals in a substantial number of artefacts and semi-finished products found from this period in the rest of Britain, Ireland, Germany, and the Middle East.

[3] Gold and tin extraction very likely began before the beginning of the second millennium BCE in Cornwall, and analysis of artefactual material suggests that Cornish metals were likely to have been exported to the rest of Britain and Ireland, the European mainland, and as far as the Eastern Mediterranean.

[11][12][7][13] Cultural and economic links between Cornwall and other communities on the Atlantic façade in the Early Bronze Age is demonstrated by similar burial practices, such as the entrance graves of West Penwith and Scilly, and metalwork finds such as the four Cornish gold lunulae, a high-status artefact which originated in Ireland.

[23][3][24] The remains of Bronze Age settlements are found in upland, lowland, and coastal habitats, and are widely distributed across Cornwall; in West Penwith, on the north Cornish coast, on the Lizard peninsula, on Bodmin Moor, and on the Isles of Scilly.

The standard explanation is that upland settlements were abandoned at this time, perhaps as a collective decision, due to climatic changes and soil degradation which may have been exacerbated by intensive agricultural practices and increased population density.

[73] Scilly features numerous settlement sites, ranging in size from individual stone roundhouses at Samson Flats, West Broad Ledge, and Little Bay, to small villages.

[74] Some of the larger excavated settlements include Nornour, south-east of St Martin's, which was occupied from c. 1500 BCE to c. 500 BCE and appears to have had limited contact with the mainland throughout this period, comprising two stone huts and a third additional building;[75] Porth Killier, St Agnes, a Bronze Age fishing and farming community comprising around three roundhouses;[76] and Dolphin Town, located at the base of a hill near the east coast of Tresco, a few metres above sea level, where a wide range of pottery, three Middle Bronze Age roundhouses, and an early field system is found.

The internal face was lined with a low wattle and daub, sod, or local sedimentary rock wall surrounding a wooden (perhaps oak) load-bearing post-ring, which carried the weight of the conical roofs, perhaps constructed with rafters made from ash, which probably used rushes or straw as weatherproof thatching materials.

[27] Another unusual structure is found at Poldowrian, Lizard, where a Bronze Age roundhouse with an internal wooden post-ring, an entrance porch, and a cobbled pathway, has stone walls made of local serpentine.

[37] Most of these boundary systems are significantly different from those of central southern and south-east Britain, and include "a bewildering array of freeform styles, unhindered by predetermined conventions of linearity or accepted orientation".

[49][3] Prominent rocks were likely to have been culturally and spiritually significant to the inhabitants of upland areas such as Bodmin Moor and Penwith, and natural features such as hills, rivers, and especially rocky outcrops were particularly important places for deciding the location or alignment of ceremonial monuments, as were existing Neolithic structures and focal points.

[29] Andy Jones states that Middle Bronze Age communities in Cornwall were "choosing to create formal ceremonial areas and buildings on the margins of settlements", with a variety of forms that included square and circular shapes, with or without roofs.

And at Trethellan, a small, 10.24 square metres (110.2 sq ft) square-floored stone building, which had been completely infilled with quartz blocks, seems to have been designed for interior darkness, appears to have only rarely been entered, and has evidence of grain deposits, all of which perhaps indicates a ritual function.

[68] A type of chambered tombs, called entrance graves, are dated to the Early Bronze Age, c. 2000–1500 BCE, and restricted to the western edge of Cornwall, mainly in Scilly, with around a dozen examples in West Penwith.

[97] Mainland entrance graves are small circular kerb-lined mounds or cairns, with an undifferentiated short passage and internal chamber, and capped with large flat granite slabs.

[48][42] In contrast, lowland and coastal settlements such as Gwithian and Trethellan were mixed arable and livestock farming societies, supplemented by activities such as hunting, fishing, or gathering wild foods.

[33][37] Evidence for Bronze Age animal husbandry is found at sites such as Gwithian where, in addition to arable and pasture farming, woods and scrub were utilized to provide forage and cover for pigs and red deer.

[2] Gabbroic clay, which is rich in feldspar, olivines, and other minerals, is found on the Lizard peninsula, which contains the largest outcrop of gabbro rock in Britain, mainly in a 1 square kilometre (0.39 sq mi) area near Zoar.

[37] At the Trethellan site, in addition to a small number of bronze artefacts, a stone mould, possible hammerstones, and copper alloy waste were found, suggesting that secondary metalworking may have been practised here.

The Trevose Head, Cataclews, and Harlyn Bay area in St Merryn parish comprises the largest collection of Early Bronze Age gold and metalwork in South West Britain.

[164][163] It has been suggested that the long and dangerous sea voyages that allowed material culture and ideology to travel along the Atlantic façade were unlikely to have taken place for economic reasons, and may have been rituals or quests of some sort, perhaps legitimizing members of elite groups or bestowing fame on those who undertook them.

[129] The Harlyn Bay site comprises the largest and richest finds from any Early Bronze Age complex in Cornwall, and may have been an important prehistoric port for the exchange of goods, ideas, monumental styles, and marriage partners within a network of coastal communities along the Atlantic façade.

[2] The introduction of new types of weapons, expanding trade networks, prestige items including gold torcs and armrings, rich barrows like Rillaton, and structural modifications to tor enclosures, may imply the existence of a small local warrior elite in Cornwall by the Late Bronze Age.

Herring argues that settlements may have produced specialized goods, perhaps necessitating an extensive exchange system organized by some sort of local authority similar to a prehistoric 'district council', which was perhaps composed of the same members of society as the lower levels of individuals, households, and cooperatives, and may have performed functions such as controlling access to summer grazing land, in the interests of the community as a whole.

It is indeed highly likely that the people of Leskernick were panning for local metals, had close contacts with distant chiefdoms, but, so far at least, our sense is of a limited vertical hierarchy.The magnitude and extent of climatic deterioration at the beginning of the Late Bronze Age has been the subject of debate for several decades, with evidence provided from palynology, ice-sheet dynamics, estimations of solar activity, and especially data from ombrogenous bogs (peat-forming mires above groundwater level).

They highlight Brisbane and Clewes' conclusion that the apparent relationship between increased areas of wet acidic grassland and the abandonment of coaxial field systems in the East Moor may be merely coincidental, rather than causal.

On Bodmin Moor, pollen core evidence is found at Rough Tor South, c. 1670–1430 BCE, where mixed oak, hazel, and birch woodland declines, with expansion of grass, ribwort plantain, and common heather.

[173] Evidence that wood was quickly grown at Scarcewater also implies that woodland was managed here, probably to provide the large amounts of timber required for roundhouse building and avoid conflict with neighbouring communities.

[3] Gary Robinson proposes that Early Bronze Age seafaring activity in Scilly would have created a sense of mutual trust and community, contributing to the creation of a "common island identity".