HIDDEN treasures dating back to the 18th century have been unearthed by a museum undergoing a £7m redevelopment.

New light has been shed on several artefacts after staff at Preston Hall Museum and Park's began in depth research into its vast collection of 90,000 items as part of the modernisation.

Two armorial (coat of arms) bowls, acquired in 1954 just after the museum in Eaglescliffe, Stockton, opened were known to be of historical importance but their cultural significance is only now being fully appreciated.

Dating back to the 1740s, the bowls are likely to be connected with the opening of Stockton Town Hall in 1735, or the transfer of the building to the then Stockton Corporation in 1744.

Each bowl is decorated with a repeating pattern of two pairs of angels, the Castle and Anchor badge of Stockton and an inscription in Latin, and are thought to be some of the first recorded examples of Chinese porcelain made specifically for an English town.

The pieces will feature prominently alongside the museum's wide and varied collection when it reopens in Summer 2012. Among these will be previously unseen treasures including sketches thought to be by the famous 18th Century Neoclassical artist Angelica Kauffman, and a watercolour by Thomas Girtin who, along with JMW Turner, played a key role in establishing watercolour as a reputable art form.

Councillor Ken Dixon, Stockton Council's Cabinet Member for Arts, Leisure and Culture, said: "It is fascinating that new light has been shed on some of the hidden gems in the Museum's collection during the preparation for its reopening.

"The armorial bowls will sit alongside established favourites of the Museum, such as George de la Tour's 'The Dice Players', along with previously unseen items forming the basis of an exciting new visitor experience."

Stockton Council's major regeneration of the museum and park includes the restoration and improvement to the Grade II listed hall, additional works within the Victorian Street, the installation of the new jetty and the re-creation of the original walled kitchen garden and orchard.

The scheme has attracted £3.8m of funding from the Heritage Lottery Fund and has also been awarded a grant of £5,000 from the Green Museums Programme run by Renaissance North-East.