John Doubleday completed a "masterly" restoration of the Portland Vase (pictured), which had been smashed into hundreds of pieces seven months prior.

John Doubleday was a British craftsperson, restorer, and dealer in antiquities who was employed by the British Museum for the last 20 years of his life. He undertook several duties for the museum, not least as a witness in criminal trials, but was primarily their specialist restorer, perhaps the first person to hold the position. He is best known for his 1845 restoration of the severely damaged Roman Portland Vase, an accomplishment that places him at the forefront of his profession at the time.

The Portland Vase is a Roman cameo glass vase, which is dated between AD 1 and AD 25, though low BC dates have some scholarly support. It is the best known piece of Roman cameo glass and has served as an inspiration to many glass and porcelain makers from about the beginning of the 18th century onwards. It was first recorded in Rome in 1600–1601, and since 1810 has been in the British Museum in London. The museum held it on loan from the dukes of Portland until 1945, and bought it from them that year. It is normally on display in Room 70.