Giacomo Leoni (1686 - 1746) (a.k.a James Leoni) was born in Venice. He was a disciple of the Florentine architectural commentator and architect Leone Battista Alberti (1404 - 1472), the mentor of the architect Andrea Palladio 1508 - 1591.

In the 18th century Leoni was to be an exponent of Palladio's work, and hence, was one of the architects responsible for what in England is loosely referred to as Georgian architecture which evolved from renaissance architecture. Having completed designs for the Elector of Palatine Leoni arrived in England in 1714 aged 28. His fresh uncluttered designs, with just a hint of flamboyance brought him to the attention of the prominent patrons of the arts.

Between 1716 and 1720 Giacomo Leoni published a four volume work on Palladio, this was followed by the ten volume translation of Alberti 's 'De Re Aedificatoria' /'On Architecture'. The first modern book on the theories and practice of architecture. Giacomo Leoni illustrated the book with his own 'Designs for Buildings Both Public and Private'. The book remains one of the truest translations of this important work. It has been a valued architectural text book to generations of aspiring architects.

Leoni did not import palladian architecture to England, that accolade belongs firmly to Inigo Jones who had designed the palladian Queen's House at Greenwich in 1616 and the more ornate Banqueting house at Whitehall in 1619. Nor was he the only architect practising the concept William Kent designed Holkham Hall in 1734 in the Palladian manner, Thomas Archer was also a contemporary, although he tended to work in a more baroque style than Leoni. Palladian architecture though was able to flourish in England because it was suited to the great country houses being built or re-modelled because (unlike in France) the aristocracy inhabited their country estates.

Giacomo Leoni's skill was to adapt Alberti and Palladio's ideals to suit the landed classes in the country-side, without abandoning the principles of the great masters. In other words he made it less austere and more 'user friendly'. He adapted his work to suit the location and needs of his clients, the use of red brick as a building component had begun to replace dressed stone during the William and Mary period. Leoni would frequently build in both, depending on availability and what was indigenous to the area of the site.

In the early 1720s Leoni received one of his most important challenges to transfer the great Elizabethan house Lyme Park into an Italienate palace, this he did so sympathetically that internally large areas of the house were unaltered completely, and the carvings by Grinling Gibbons were left intact.

The transformation at Lyme was a success, if a little spoilt later by the addition of a box like structure surrounding the centre pediment in the 19th century by the English architect Lewis Wyatt ; this squat tower was is in the place of Leoni's intended cupola rejected by the owner. Leoni broke with one Palladian tradition at Lyme, (probably in consideration of the northern climate) he provided a grand staircase to the principal floor or 'piano nobile' inside, by placing the main entrance on the ground floor. However, Lyme Park with its massive ionic portico and matching wings sitting on their rusticated basement, plus the internal courtyard, is one of the most pure Palladian buildings to survive from that era.

In 1730 Leoni was commissioned by the 2nd. Earl of Onslow to build what is probably his greatest British masterpiece Clandon Park. Inside and out the house is an architectural triumph, now developing his own style Leoni mixed Baroque and Palladian styles. The house was built of a fiery red brick, with the west front dressed with stone pilasters and medallion ornamentation, the interiors were in contrast to the exterior, the huge double height marble hall is in muted stone colours to provide a foil for the magnificent colours of the adjoining suite of state rooms. The house today remains largely unaltered, the interiors were altered slightly later in the 18th century, but here the house was fortunate, the changes were made in the style of Robert Adam so hence were sympathetic to Leoni's original intentions. The marble hall is one of the most important 18th century rooms in England as are the magnificent plaster work ceilings.

However Leoni's 'user friendly' reputation came unstuck when he designed for clients clearly unaware of the intricacies of palladian architecture:- Leoni had been commissioned by Edward and Caroline Wortly to rebuild the decayed Wortley Hall. A magnificent residence arose. However, in 1800 the Wortleys complained they were unable to move in as the architect had forgotten to build a staircase. One hundred years later a Duchess of Marlborough made the same complaint against Sir John Vanbrugh's Blenheim Palace, both owners had rather missed the point of a house built on a 'piano nobile' design. A piano nobile is the principal floor, usually above a lower floor or semi-basement, it contains all the rooms necessary for the grandees who inhabit the house, it usually consists of a central salon or saloon (the grandest room beneath the central pediment), on either side of the Saloon (in the wings) are often a, slightly less grand, withdrawing room, and then a principal bedroom, after that perhaps would follow a smaller more intimate room. The point both the Duchess and owners of Wortley had failed to grasp was that the owners lived in 'state' on the 'piano nobile' and had no need to go upstairs, hence only secondary/back staircases would reach these floors occupied by children, servants and less favoured guests. Indeed, these houses often did have a grand staircase, but it was external - the elaborate flights of stone steps to the main entrance on the piano nobile. From photographs of Wortley Hall, one can see the large tall windows of the 'piano nobile' on the lower floor, and the much smaller windows of the secondary rooms above. It did not require a 'grand' staircase'. Wortley Hall survives today as an hotel, the owners still tell the story of the forgetful architect.

It was not only grand mansions Giacomo Leoni designed, his lesser designs included:- an octagonal garden temple for Lord Orkney in 1735 at Cliveden, an elegant arch in purest palladian tradition for the Marquis at Buckingham at Stowe and a Portland stone bridge at Stone Court Carshalton. Leoni is thought to have designed a new church when working for the 8th Lord Petre at Thorndon Hall Essex. The original church had been swept away to make room for the new mansion he was designing there.

Today his style of architecture seems quintessentially English, the fact that it was pure Italien at the time of its design is now forgotten. So indigenous to England does it seem now, that when in 1912 a time of huge pride in all things British, Sir Aston Webb's new principal facade at Buckingham Palace was probably inspired by Leoni's 'Italien palazzo' at Lyme Park no-one raised an eyebrow. The latest BBC adaptation of that most English of books Jane Austen's Pride and Prejudice took place in the shadow of that same Italien front at Lyme.

Giacomo Leoni died in 1746. By this time his work had been an inspiration to a whole new generation of British architects including Robert Adam. It could be argued that designs he championed have been taken up today, by the arbiters of good taste, although his impressions of the modern neo Georgian housing estates cannot be imagined; his influence is there, because rich and poor both like his style as much today as they did three hundred years ago.