THE finest interior I know of in Scotland is the Playfair Library Hall in the University of Edinburgh’s Old College building. It was named after William Henry Playfair, the man who designed the university’s Old College and New College and who is remembered as the greatest architect in Edinburgh’s history, responsible for some of the capital’s signature buildings.

Yesterday was the bicentenary of the death of William Henry’s uncle John Playfair, one of the great figures of the Scottish Enlightenment. The anniversary has accorded me the opportunity to remember the Playfair family and the mark they made on Scotland and the world.

As I recorded last week, the four Playfair brothers – John, James, William and Robert – were the sons of the Reverend James Playfair, minister of the Church of Scotland at Benvie west of Dundee, and his wife Margaret nee Young.

All four brothers were brought up to be “lads o’pairts” with an education at home that was wide-ranging.

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Last week we saw what became of the mathematician and astronomer John and William, the engineer turned spy and statistics genius, and this week we’ll examine the life and career of James and more especially his son William. Of Robert we know little except that he was a solicitor in Edinburgh.

James Playfair was born on August 5, 1755, the youngest son of Rev Playfair. We know next to nothing about his early life or training as an architect, but as the Dictionary of Scottish Architects states: “The last 10 years of James Playfair’s life are recorded fully as his professional journal survives in the National Library of Scotland and his drawings in the Soane Museum and RIBA Drawings Collection.”

We do know that by 1783 he was established as an architect both in Scotland, where the powerful Henry Dundas was a patron, and in London. Dundas asked him to design Melville Castle, his home in Midlothian, after Playfair won a competition to design Forfar’s Town and County Hall. James Playfair also designed Kirriemuir and the Glens Parish Church and the Lynedoch Mausoleum at Methven kirk.

As can be seen from his drawings, which are among hundreds of works of his surviving in the National Library of Scotland and Sir John Soane’s Museum in London – the architect Soane was a personal friend – Playfair was an excellent draughtsman.

Like so many Scots at the time of the Enlightenment, James Playfair was influenced by his trips to the continent and he exhibited many drawings of Italian scenes in particular, notably at the Royal Academy in London.

His neo-classical style can be seen at its best in his finest work, Cairness House in Fraserburgh. James died at the age of 39 on February 23, 1794, when his son William Henry was just three.

Perhaps William inherited his talent as a draughtsman from his father but he was most certainly influenced by James Playfair’s love of the neo-classical. That inherited love would change the face of Edinburgh.

Born in London on July 15, 1790, Playfair went to Edinburgh to stay with his uncle John when he was 14, and he completed his education before taking up apprenticeships to architects in Edinburgh and London.

Playfair was happy to follow in the footsteps of the Adam brothers and in 1817, he won the competition to finish Robert Adam’s design for Edinburgh University Old College and he would later add the New College.

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After designing Dollar Academy, he was commissioned to plan the area north of Calton Hill in the capital – the Third New Town as it became known. On Calton Hill itself he designed the City Observatory and the monument to his uncle John – many people mistakenly think the monument is dedicated to William – and later he also designed the Dugald Stewart Monument and the National Monument.

The latter structure is known as “Edinburgh’s disgrace” because it was supposed to be a Parthenon-resembling monument built by public subscription to commemorate the dead of the Napoleonic Wars but ran of out money before it was even a quarter finished.

That successful Calton commission saw Playfair corner the market in public works in Edinburgh, and the fact that Edinburgh is called the Athens of the North is largely due to his designs in the neo-classical style. With his contemporary Thomas Hamilton also designing the neo-classical Royal High School, Playfair’s imprint on Edinburgh was vast.

Yet curiously, Playfair never visited Greece or Rome, the furthest he travelled being Florence where he went to visit his doctor brother James in a bid to cure his chronic bronchitis.

The list of works that he designed in Edinburgh says it all: in chronological order of design they include the Royal Institution, now the Royal Scottish Academy; part of George Heriot’s Hospital; the Advocates Library; Surgeon’s Hall; 105 George Street; St Stephen’s Church; Bonaly Tower; Colinton House; Donaldson’s Hospital; the Free High Church and College, and many more.

In addition he remodelled Floors Castle for the Duke of Roxburghe and designed St Ronan’s Wells and the Pump Room at Innerleithen.

One of his last and greatest designs was his 1850 work for the National Gallery of Scotland, but he did not live to see it completed. His health drastically declined after he completed the gallery design and he died on March 19, 1857, two years before the National Gallery opened.

William Henry Playfair is buried in Dean Cemetery and there is a statue of him atop his monument in Chambers Street, Edinburgh, outside the National Museum.