Archaeologists have made an exciting discovery in the Queen Pool at Blenheim Palace prior to dredging work.
They believe they have uncovered the remains of a 14th century watermill complex.
The stone structures were discovered as part of preliminary work ahead of a major dredging project.
Wessex Archaeology has been surveying and excavating the site to ensure no historical remains are affected by the works.
It is believed the watermill is associated with Woodstock Palace, a royal hunting lodge that played host to 16 British monarchs over its 700-year history.
Everyone from Ethelred the Unready to Henry VIII spent time there.
The lodge, which was demolished in 1720 to make way for Blenheim Palace, was the birthplace of the Black Prince, the eldest son of King Edward III, and the heir apparent to the English throne.
He died before his father and so his son, Richard II, succeeded instead.
And it was used as a temporary prison for Queen Elizabeth I.
One Thomas Wyatt led a protestant uprising to try to prevent the Queen Mary I marrying Philip of Spain, which would firmly re-establish Roman Catholicism in England.
The plan was to depose Mary and put her protestant sister, Princess Elizabeth, on the throne.
Elizabeth knew nothing of the plot, which failed - but she was imprisoned as a precaution, first in the Tower of London and then in the lodge at Woodstock.
Elizabeth's journey to Woodstock took four days and she was cheered by the common people all along the route.
She scratched the following words on a windowsill:
Much suspected by me,
nothing proved can be,
Quoth Elizabeth prisoner.
It was Mary's Spanish consort, Philip, who slowly persuaded the queen to release her and Elizabeth was allowed to leave Woodstock in April 1555 after nearly a year under house arrest.
Andrew Manning, Wessex Archaeology’s regional manager south and west, said: “As part of the Queen Pool Restoration Project, we have been involved in the initial archaeological work within the World Heritage Site at Blenheim Palace.
“The project involves removing significant quantities of silt from the lake and depositing the material within part of the North Park to create a new landform to the north of the lake.
“Accordingly, all aspects of the project will be carefully monitored and assessed by archaeologists to ensure any revealed remains are recorded and protected.
“The most significant discovery is stone water channels, which would have been part of a medieval mill site, recorded as being demolished in 1334, and which was partly excavated in the mid-1970s.
“The remains found this year comprise part of the stone-lined mill race, directing water from the mill and are surprisingly well-preserved and substantial.
“Drone surveys clearly show the stone races extending into the current lake and with evidence of further structures visible below the lakes surface,” he added.
According to historical records a small pond – known as Queen Pond or Pool had existed on the present site since the Middle Ages, alongside a second fishpond, known as King’s Pool.
Both these water bodies were associated with the Woodstock Palace.
In 1976 archaeological excavations of a ‘Medieval water mill site’ linked the original Queen’s Pond to the ‘site of a mill pond’ created by damming tributaries of the River Glyme.
Queen Pond may originally have been created as a retained body of water used to drive the mill wheel.
The pond is said to have been named after Queen Philippa, consort of King Edward II, mother of, Edward, the Black Prince, who was born at Woodstock in 1330.
The name was retained by ‘Capability’ Brown for one of the lakes created when he flooded the valley to make his great waterworks.
Once fully recorded, the remains will be carefully recovered and logged for future reference.
The dredge, which gets under way this month, is one of the largest civil engineering projects ever undertaken at the site.
Leading wet civil engineering contractor Land & Water will remove 300,000 cubic metres of silt - enough to fill Wembley Stadium - and return the ‘Capability’ Brown-designed lake to its original depth of two metres from its current shallows of 30cm.