Three men and a teenage boy have admitted their parts in a burglary at Cambridge's Fitzwilliam Museum earlier this year.
The raid saw millions of pounds worth of ancient Chinese artefacts stolen.
The 15-year-old boy from London pleaded guilty to burglary. Robert Smith, 24, of Hockenden Lane, Kent, Steven Coughlan, 26, of Eleanor Street, London, and a 29-year-old man from London who cannot be named for legal reasons, all pleaded guilty to conspiracy to burgle.
Det Chief Insp Jim McCrorie said: “Today’s guilty pleas follow a large scale police operation and a lot of hard work to ensure those involved in this burglary were caught and convicted."
He said the items - believed to be worth millions of pounds - have yet to be recovered.
“Sadly the items, which are of huge cultural significance, have still not been traced but we remain committed to pursuing new lines of enquiry that could lead to us recovering them."
All four will be sentenced on September 28 at Cambridge Crown Court.