WOMEN, said George Fox, are the spiritual equals of men.

It was a radical idea for its time (Fox was born in 1625) - but no less than you would expect from the founding father of the Quaker movement.

It is certainly a philosophy that York's Quaker school for girls, The Mount, has embraced with some success. Among the women the school has educated are the novelists Margaret Drabble and AS Byatt (actually sisters); Dame Judi Dench; Elizabeth Fry, the 19th-century campaigner for the better treatment of women prisoners; and Dame Jocelyn Bell Burnell, one of Britain's leading radio-astronomers and co-discoverer of pulsars.

Science, in fact, has always played an important part in the education provided by the school, says Sarah Sheils, author of a new book Among Friends: The Story Of the Mount School. From quite early on in its history, girls enrolled at the school "studied natural history, as well as French and Latin, a lot of maths and English. It was quite forward-looking for its day." The origins of The Mount School date back to 1785 when wealthy York Quaker William Tuke and his wife, Esther, founded The Friends' Girls' School in Trinity Lane, off Micklegate.

In the 1660s, one of Tuke's York ancestors, a local blacksmith's son also named William Tuke, suffered persecution along with other York Quakers. He was twice imprisoned in the Kidcote, the gaol beneath the chapel that used to stand on the old Ouse Bridge. His property was also confiscated because of his religious beliefs.

By the late 1700s, however, times were easier for Quakers, and the later William Tuke had become a prosperous tea merchant. As well as being a leading member of York's Quaker movement, he also left an enduring legacy, which includes today both the Mount School itself and The Retreat psychiatric hospital, which he founded in 1796.

The Friends Girls' School itself did not survive that long. In 1796 it moved to larger premises in Tower Street, near to the Tukes' home and also to the Friends Meeting House. But in 1812, the school was forced to close - largely, writes Sarah, because of inflation and economic problems caused by the Napoleonic wars. After a York Friends' Boys' school was founded in 1829, however, a site for a new girls school was found by four leading Quakers - Samuel Tuke (William's grandson), William Alexander, Thomas Backhouse, and Joseph Rowntree, founding father of the Rowntree dynasty in York. The school opened in Castlegate House in 1832 and has been in existence ever since - changing its name to The Mount School when it moved to The Mount in 1857.

Among Friends: The Story Of The Mount School by Sarah Sheils is available from The Mount School