The organization behind some of the famous stained glass in York Minster is celebrating its 40th anniversary.
York Glaziers Trust, which cares for, restores and conserves the Minster's stained glass, has become one of the most well-respected stained glass studios in the world.
Its projects include conserving the Rose Window after the fire of July 1984, and the painstaking ten-year restoration of the St William Window, which was unveiled in June.
The glaziers are now working on 700-year-old glass from the Minster's Chapter House vestibule; some of the oldest and most fragile glass the trust has dealt with.
They are also restoring the Great East Window, which will form the largest conservation project of its kind in Europe.
York Glaziers Trust was formed in 1967 following suggestions by Eric Milner-White, who was Dean from 1941 to 1963.
Since then, it has grown form three craftsmen to 11 skilled glaziers and conservators.
It was awarded a Heritage Lottery Fund for its "In The Beginning" project in 2006, to work on the Great East Window, which is one of the world's finest pieces of medieval stained glass.
It has been mended many times, using lead that has gradually obscured the window. Now glaziers are removing as many heavy lines as possible to try and restore it to its 15th century glory.
Although the trust works primarily on the stained glass in the Minster, the expertise of the glaziers is shared elsewhere.
The trust has worked on glass across the UK, including the conservation of medieval glass in a number of colleges at Oxford University.
* To mark the 40th anniversary celebrations, an exhibition of work about the trust in York Minster will run between Monday, November 19 and Friday, February 1. Normal Minster admission charges apply, but York residents can use their Minster passes to view it free of charge.
To get a pass, pick one up in York Minster or send an SAE to The Visitors Department, St William's College, College Street, York, YO1 7JF.