A 220-year-old time capsule containing coins, documents and other artefacts left by US founding fathers Samuel Adams and Paul Revere has been opened by Massachusetts officials.

The corroded 10-pound (4.5kg) brass box, removed from beneath the State House last month, was painstakingly dismantled and unpacked by custodians at Boston's Museum of Fine Arts.

Time Capsule Boston
The time capsule that was placed under a cornerstone of the State House in 1795, is seen before being opened at the Museum of Fine ArtsBrian Snyder/Reuters
Time Capsule Boston
Executive director of the Massachusetts Archives, Michael Comeau, and MFA conservator Pam Hatchfield open a time capsule, which was placed under a cornerstone of the State House in 1795, at the Museum of Fine Arts in BostonBrian Snyder/Reuters
Time Capsule Boston
Conservator Pam Hatchfield shows the engraving on the inside of the lid of the time capsuleBrian Snyder/Reuters

Among the items in the box were two dozen coins, a bronze medal portraying George Washington, a silver plate made by Revere, and colonial records and five tightly folded newspapers.

A portion of one of the papers that was visible showed a listing of the arrivals of whaling ships from various ports to Boston.

Time Capsule Boston
Newspapers found in a 1795 time capsuleKayana Szymczak/Getty Images
Time Capsule Boston
Kayana Szymczak/Getty Images

The oldest coin in the box was a 1652 "Pine Tree Shilling", made at a time when the colony didn't have royal authority to create its own currency.

While some of the coins appeared corroded, other items were in good condition and fingerprints could be seen on the silver plaque.

Time Capsule Boston
An engraved silver plate removed from a time capsuleBrian Snyder/Reuters
Time Capsule Boston
Silver and copper coins, including a 1652 Pine Tree ShillingKayana Szymczak/Getty Images
Time Capsule Boston
Coins, including a copper medal depicting George WashingtonBrian Snyder/Reuters

The capsule was first placed under the cornerstone of the 18th-century State House building, a Boston landmark topped by a gilded copper dome made by Revere's company, on 4 July, 1795 in recognition of America's 20th anniversary of independence.

Adams was then governor of Massachusetts, and Revere a colonial icon and silversmith best known for alerting Colonial fighters to the approach of British Forces before the battles of Lexington and Concord in 1775.

The contents were shifted to what was believed to be a copper box in 1855 and placed back into the foundation of the Statehouse. The box remained there until it was rediscovered last year during an ongoing water filtration project at the building.

Time Capsule Boston
The box that held the contents of the 1795 time capsuleKayana Szymczak/Getty Images

Massachusetts state secretary William Galvin said he expects the items will be on display at the museum for a period of time, but that eventually they will again be returned to the foundation to be discovered by a future generation of Bay State residents.