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Uncovered: Oldest watermill in London
Louise Jury16.02.09
The earliest watermill ever found in London is being studied by archaeologists.
The medieval mill at Greenwich Wharf is being surveyed by experts from the Museum of London in advance of a building development.
The 12th century structure would have measured more than 30ft by 36ft at the foundations with a waterwheel more than 20ft in diameter.
It has been preserved against centuries of damage by riverside peat deposits. Carpenters' or millwrights' assembly marks are clearly visible on the timbers.
Archaeologist Simon Davis said tide mills were probably numerous along the Thames foreshore at this time. Four were mentioned in Greenwich in the Domesday book of 1086.
"However, little evidence of mills in use in the early medieval period has been found on archaeological sites, so the discovery of a 12th-century tide mill is very significant and exciting," he said.
The find is similar in design to Roman mills. What has survived is the water trough, carved from a single log, and a carved section of the waterwheel itself with paddles.
Dendrochronological analysis - where tree rings are counted - dates the trees' felling to 1194.
Mills worked by drawing in water from the river as the tide rose and releasing it as it fell, powering the mill.
This mill was likely to have been used for grinding corn and probably belonged to a nearby monastery that was part of an order from Ghent in Belgium.
Researchers will investigate whether monastery records can shed light on the workings of the mill. Mr Davis said it was so large, it must have been a commercial operation. "The story of the life of the mill is yet to be told," he said.
Fragments of millstone were found underneath the structure, apparently used as packing material for the foundations.
English Heritage is working with archaeologists, the developers and Greenwich Borough Council to complete the recording of the site.
Timbers have been sent to York for conservation using the same silicon techniques that preserved the Mary Rose Tudor warship.
