Editor’s Note: This article was originally published by The Art Newspaper, an editorial partner of CNN Style.

CNN  — 

Conservation work that began 20 years ago on a giant set of 16th-century tapestries is almost complete: 12 down – as the most recently cleaned and repaired panel goes back on the wall at England’s Hardwick Hall, where they have hung since 1592 – and one to go, now on its way to the workshop.

The job has been the lengthiest textile project ever carried out by the British heritage charity, the National Trust. Each panel is around six meters (20 feet) tall, and the 13 add up to more than 70 meters (230 feet) in length, the largest surviving set in England.

The tapestries were bought by a suitably towering personality, Bess of Hardwick, who outlived four husbands and became richer each time she was widowed.

A view of Hardwick Hall, where the tapestries have hung for centuries.

She built and remodeled English stately homes on an imperial scale, including Chatsworth House, family home of her second husband, and her own astonishing residence, Hardwick Hall in Derbyshire, famously dubbed “more glass than wall” at a time when any glass window was a costly luxury.

The tapestries were originally woven in Flanders, Belgium, for Sir Christopher Hatton, for his own vast new house, Holdenby Hall in Northamptonshire, and sold after his death in 1591 to meet heavy debts.

Bess paid the then-enormous price of £326, 15 shillings and 9 pence, roughly the equivalent of £128,000 ($182,000) today, according to the National Trust.

She brought the tapestries to Hardwick Hall, where they have remained ever since, and had patches of her own coat of arms stitched and painted over Hatton’s. His golden hind emblem was also converted into a Cavendish stag by adding painted antlers.

Textile conservators from the National Trust working on one of the many tapestries at the center of the restoration project.

The conservation work included replacing thousands of broken threads, strengthening points of heavy wear, and recording and removing some historic repairs made out of patches cut from other old tapestries. All the panels were strengthened by being stitched onto a linen backing, and then given a cotton lining.

Work on the 13th panel, funded by a private donation of more than £287,000 ($407,000), should be finished by 2023, completing the epic project. The 12th panel will be left to be admired on its own for at least two years, without reinstating the portraits which had hung on top of it.