Archaeologist Sarah Leveille cleaning the northeast corner of the mill. The millwright’s assembly mark is visible below the mortice joint. © Museum of London Archaeology
Archaeologists have uncovered the medieval equivalent of the London Eye at Greenwich Wharf under the site of a new development.
The 12th century tide mill would have measured an enormous five meters in diameter and would have dominated the Thames embankment. The wooden structure measures 10 metres by 12 metres at its base and represents an extraordinary example of medieval engineering.
The mill worked by drawing in water from the river as the tide rose and then releasing it as the water fell. An enormous channel fashioned from a single oak beam then channelled the water and it is this that has been found preserved in the riverside peat deposits along with a substantial fragment of the actual wheel.
The Museum of London Archaeology field team recording the mill, with the River Thames in the background. The dark peat deposits surrounding the structure preserved the timbers. © Museum of London Archaeology
Simon Davis, Contract Manager for Museum of London Archaeology, said: “Tide mills may have been numerous along the Thames foreshore in the early medieval period. Four mills in Greenwich are mentioned in the Domesday Book of 1086 and over 6000 mills were recorded across the country at this time.
“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 at Greenwich is very significant and exciting.
“Detailed recording of the find following its excavation and dismantling by the Museum of London Archaeology field team will enhance our understanding of milling technologies and early medieval economies.”
A bird’s-eye view of the mill showing the massive central timbers that would have supported the waterwheel. The bays either side of the waterwheel are likely to have housed gears for the millstones. © Museum of London Archaeology
Dendrochronological analysis (the counting of tree rings) has dated the tree's felling to 1194 and the size of the structure is testament to the craftsmanship and engineering skills of its makers.
Mark Stevenson of English Heritage said: “The discovery of the remains of this wooden tidal mill at Greenwich Wharf, Greenwich, is likely to be the earliest medieval example of this type to be excavated in London.
“English Heritage is working closely with Greenwich Borough Council, the developers and Museum of London Archaeology to ensure that this rare and important discovery is carefully recorded.”
The waterwheel has been carefully dismantled and the site will be carefully monitored by English Heritage. Key sections including the trough and the fragment of waterwheel are currently undergoing conservation work with the York Archaeological trust.
