Leoni, Giacomo (c.1686–1746). Supposedly a Venetian architect, he spent most of his life in England from c.1713. Before that he was in Düsseldorf, where he assisted in the design of Schloss Bensberg, near Cologne (1705–16). While in Germany he worked on a treatise on the Five Roman Orders of architecture which indicates that the idea of publishing a version of Palladio's Quattro Libri was already in his mind before he settled in England and did just that. The translator of the texts was Nicolas Dubois, and Leoni prepared the drawings on which the engravings were based: the results of these labours appeared as The Architecture of A. Palladio, Revis'd, Design'd and Publish'd by Giacomo Leoni, a Venetian: Architect to his most Serene Highness, the Elector Palatine with texts in English, French, and Italian (1715–20). It was the first English edition, illustrated with large engraved plates instead of the rather crude woodcuts used by Palladio himself, and was an outstanding and immediate success, helping to promote Palladianism and probably helping to spark Burlington's interest in the cause. In 1726–9 he published The Architecture of Leon Battlsta Alberti.

Leoni designed a number of houses including Queensberry House, Burlington Gardens, London (1721—an important prototypical Palladian town-house), Lyme Park, Ches. (c.1725–35), Argyll House, King's Road, Chelsea, London (1723), Clandon Park, Surrey (c.1730–3), and Alkrington Hall, Lancs. (1735–6). All had borrowings from Inigo Jones and Palladio, but he was not a purist, and there is more than an echo of the Baroque in his work, suggesting a position closer to that of Gibbs than of Campbell. It is arguable that he was more influenced by than influencing British architecture.

Bibliography

J. Brown (1985);
Colvin (1995);
E. Harris (1990);
Leoni (1742, 1755);
Summerson (ed.) (1993);
Jane Turner (1996)