Medieval Period (AD410 - 1500)
Early Medieval - AD 410 - 1066
Tin was in considerable demand for manufacturing
both bronze and pewter and there is strong archaeological evidence
for trade between Cornwall, the eastern Mediterranean and northern
Europe.
The Trewhiddle Hoard (Pentewan) of late
ninth-century silver is thought to have been hidden from invading
Danes in a working tin stream. An oak tinners’ shovel found in
Boscarne tin stream (Bodmin Moor) has been radiocarbon dated to
between AD 635 and AD 1045. Church bells, whose bronze depended on
Cornish tin, were widespread by AD 1000.
Later Medieval 1066-1500
Cornwall and Devon sustained an internationally
important medieval tin industry. Shallow mining effectively mapped
the major areas where tin occurred; copper at this time still
being of little commercial interest.
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The Stannaries [location
map]
The importance of the tin industry in the medieval
period was recognised by the establishment of a special legal
framework. It was first enshrined in a charter from King John in
1201 that included a number of pre-existing common law practices.
The charter gave privileges to the tinners, and their industry, in
return for which they paid a special tax, that was calculated at
the time of coinage. From the earliest records in the twelfth
century through to abolition in 1838 the tax levied on tin
production in Cornwall was at double the rate of that applied in
Devon.
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The areas of jurisdiction were defined as eight
Stannaries; four in Devon and four in Cornwall. In Devon they
divided Dartmoor into quadrants. In Cornwall they were: Foweymore
(present-day Bodmin Moor); Blackmoor (centred on Hensbarrow Moor
north of St Austell); Tywarnhayle (a triangle approximately
bounded by St Agnes, Truro and Scorrier); and the united
Stannaries of Penwith & Kerrier (roughly corresponding with the
respective political districts of today). Each possessed at least
one designated Stannary town where tinners were obliged to present
their blocks of smelted tin that were tested for purity before
taxes were collected. Tavistock was a Devon Stannary town.
When the Duchy of Cornwall was established in 1337 coinage formed
a significant source of revenue.
The Duchy was also probably the
largest single mineral lord in the south-west. Most of the fundus
(river-bed) of the principal rivers, and some of the estuaries,
were owned by them, and considerable royalties were gained from
tin-streaming activities in those areas. |
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In 1497 the Cornish revolted against new Stannary laws imposed by
Prince Arthur, Duke of Cornwall. As a result the charters were
confiscated, to be renewed by the Charter of Pardon issued in 1508
in return for a payment of £1,000. This included the right,
through the Stannary Parliament, to veto any statute or
proclamation which was ‘to the prejudice’ of the tinners. The
combined Stannaries had their own Stannary regiment 1798-1913.
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Medieval tin-streaming
Tin-streaming technology in Cornwall and Devon was
similar to that which was used elsewhere in Europe during this
period. This was documented by a number of contemporary European
writers, notably Biringuccio (1540), Agricola (1555) and Ercker
(1574). They show an industry that had already begun to develop
sophisticated water-powered machinery, in particular for pumping
small-scale shaft mines, and was using extensive adits to provide
natural drainage wherever possible.
By 1602, however, Carew was making
plain the limitations of the available technology as mines became
deeper:
For conveying away the water they pray in aid of sundry devices,
as adits, pumps, and wheels driven by a stream and interchangeably
filling and emptying two buckets, with many such like, all which
notwithstanding, the springs begin to encroach upon these
inventions as in sundry places they are driven to keep men, and
somewhere horses also, at work both day and night without ceasing,
and in some all this will not serve the turn. |
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Tin streaming, and shallow
shaft mining, provided employment and wealth far beyond that to be
expected from such a remote and poor agricultural area. Countless
valleys in Cornwall and west Devon were turned over for tin. There
is massive evidence of tin streaming manifested in hundreds of
hectares of man-made landforms on Dartmoor (Devon), Bodmin Moor,
West Penwith, on Goss Moor, Breney Common and Redmoor, as well as
in the wooded valleys of the region that drain the mineral rich
areas. These remains are well documented and many have been
surveyed in detail. The removal of millions of tonnes of
overburden, together with the finely crushed waste of
ore-processing resulted in the rivers and estuaries in the region
becoming heavily silted. The Plym, Looe, Fowey, Fal, Carnon,
Helford, Cober, Hayle and Red Rivers all have mineral detritus
many metres deep. Tidal limits have been progressively pushed
downriver so far that former ports were subsequently marooned
amidst salt marsh. The landscape of the region’s medieval tin
mining industry represents the most extensive remains of pre-1700
mining in Britain.
Tin smelting in blowing
houses
Tin was smelted by mixing the simple oxide ore (cassiterite
SnO2) with carbon (usually peat or wood charcoal) and reducing it
in a granite furnace blown with air by means of a water-wheel
bellows. In 1198 William de Wrotham, first Warden of the
Stannaries, refers to two smelting processes. The first (probably
a crude smelting) took place at the mine whilst the second took
place at the Stannary town for taxation purposes.
By the mid-fourteenth century this practice was
succeeded by single-process blowing houses and a number of these
survive, particularly on Dartmoor. Blowing houses produced the
purest grade of tin (grain tin) from alluvial ore. This metal
carried a premium price, above that of ‘mine tin’, and was
favoured by the glass-making industry. It was also used in
coloured glazes and in acid dyes for carpets and fabrics.
Fuel and the early mining
industry
During the thirteenth and fourteenth centuries oak
woodland in Cornwall and Devon was managed to make charcoal for
tin-blowing. Tinners also needed timber for their shallow shaft
workings. Old oak woodlands in Cornwall such as in the Luxulyan
Valley or the thickly wooded banks of the river Fowey, show the
multiple trunks of ancient coppiced trees and the platforms where
the charcoal was made. On the moorland peat was cut to make peat
charcoal. Goonhilly Downs, Bodmin Moor and Dartmoor were important
sources for this fuel.
Medieval silver mining in
the Bere Alston peninsula
The Bere Old Mines, together with those at Combe
Martin in north Devon, dominated English silver production until
the late sixteenth century. In the late thirteenth and fourteenth
centuries a fundamental change took place in local mining
organisation when the Crown - apparently prompted by the desire to
maximise its income from silver mining - worked the Devon
silver-lead mines directly by shaft mining. For the first time
small-scale independent operations were replaced by a relatively
large-scale capital-intensive mining organisation that laid the
foundation for an entrepreneurial system - the Cornish tribute.
This dominated non-ferrous metal mining, in Britain and in many
overseas mining fields into the modern period.
Skilled miners were drawn from other British lead
mining districts, many of whom were pressed into service. Workings
were initially shallow but adit drainage was required by 1297 when
output peaked. In the early fourteenth century the workings were
rich but again impeded by water. Crosscut drainage adits had to be
driven deeper. When the Black Death hit the South West of England
in 1348/9 the mines were reduced to the reworking of slag
residues. Underground working was abandoned. |
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