Merton Priory is a landmark rich in history but little known in London.

Saint Thomas Beckett was educated at the priory, King John regularly stayed there and in 1236 Henry III prepared the Statute of Merton in the priory's cloisters, establishing parliamentary law throughout England.

A grand-scale religious powerhouse in the 12th century, the abbey was destroyed during the dissolution of the monasteries in 1538 and all that remains today is an archaeological site beneath the Sainsbury's car park in Colliers Wood.

Now the opening of an exhibition celebrating 900 years since its foundation aims to shed light on the "undeservedly unknown national treasure".

Chronicling the priory's rich history, the exhibition at the Museum of Wimbledon, which opens this weekend, also reveals plans funded by the National Lottery for extensions to the Chapter House Museum, where the archaeological remains are on show to the public.

The exhibition's curator, Cycil Maidment, 80, said: "Merton Priory was very important in its lifetime and royal weddings took place there, big decisions were made and statutes were written so that's why there should be some recognition of Merton Priory."

Organised in a series of eight storyboards charting different periods of the site's complex history, the exhibition includes coverage of recent digs by the Museum of London and a variety of significant historical documents and work done by former councillor Richard Chellew on the Statute of Merton.

Visitors will also be able to see photographs of some of the beautiful churches of Augustinian Priories that have escaped destruction by Henry VIII and still exist today.

Cassandra Taylor, museum chairman, said: "We wanted to do something on the 900th birthday of Merton Priory because it's hugely important in local history."

Merton Priory is 900 years old; Museum of Wimbledon, 22 Ridgway, Wimbledon; until August 31; Wednesdays, 11.30am to 2.30pm, Saturdays and Sundays, 2.30pm to 5.30pm; admission free;, 020 8296 9914