A cup presented to a 17th century Devon MP could fetch up to £50,000 when it is auctioned later this week.
The silver-gilt state cup and stand were gifted to John Sparke, who was MP for Plymouth from 1677 until his death in 1680.
Mr Sparke, who married Mary, daughter of Sir Alexander Carew Bt, in 1663, was from a politically active line. His grandfather, also John, had been mayor of Plymouth in 1583 and 1591.
The cup and stand are pricked with the Sparke family arms and those of the city. The presentation was recorded in the council minutes for 1679-80: "£37 10s paid for a large silver salver Cawdle Cupp and cover embost and thick washed with gold weighing 75 ounces, given to John Spark (sic) one of the burgesses, in token of the respect and gratitude of this town for his faithfull and diligent service."
The cup and stand passed out of the Sparke family in 1714 via a bequest to a godson, John Molesworth of Pencarrow, between Wadebridge and Bodmin in Cornwall. It was passed through 12 generations of the family until Sir Arscott Molesworth, the 15th baronet, sold it in 1994.
The engraving on both the cup and the stand are regarded as a particularly sophisticated example of prick-dot engraving which can be seen mainly on Westcountry silver.
The cup and stand will go under the hammer at Bonhams in London on Wednesday. The lot is estimated at £40,000-50,000.