If Paul Colnaghi had emigrated to America in 1783, as Benjamin Franklin advised him to do, London would be without one of its oldest and most celebrated Galleries. Instead, Colnaghi went to work for Anthony Torre, whose father had established businesses in Paris and London. Anthony Torre's London premises enjoyed a reputation for stocking the finest wares of celebrated engravers. When Paul Colnaghi joined him in 1783, they soon moved to a superior address at 132 Pall Mall, and by 1788 the younger Colnaghi had taken control of the business. Paul Colnaghi was to raise the small business to a status unsurpassed in the art-dealing world. There were difficulties in the beginning; as a result of the French Revolution and the ensuing disorders, trade with the Continent suffered. Colnaghi, however, managed to weather the storm by a series of adroit moves. During 1792-1797, he published what is probably the most famous series of English stipple engravings, The Cries of London. At the same time he began to issue engravings of military, naval and patriotic heroes. For instance, on November 7, 1803, when news of Nelson's victory and death at Trafalgar reached London, Colnaghi had already commissioned a portrait engraving. Paul Colnaghi's connections with Europe, his knowledge of languages, and his integrity in business were all of great help to him during this turbulent period. He was able to supply the Government with views of beleaguered towns on the Continent, thus providing information for the besieging armies which would otherwise have been lacking.
In this way, he became known to many important officials, and the shop at 23 Cockspur Street, where he had moved in 1799, became a meeting place for the ‘Upper Ten Thousand'. Colnaghi was appointed print seller to the Prince Regent who employed him to arrange the Royal Collection. He gave a monthly 'three o'clock levee, crowded with beauty and fashion' where 'English marchionesses, foreign princes, knights, dames and squires of high degree met as a club'. As if to immortalize these gatherings, a series of engraved portraits of 'Royal and Noble Ladies' was issued by The Colnaghi Gallery. Dominic, Paul's son, maintained close relationships with the best artists of the day, in particular with John Constable who often bought landscape engravings, and with Richard Parkes Bonington. As a print seller, Colnaghi's fortunes, from the very beginning, had been linked to technical advances in the reproduction of works of art. Therefore, it should come as no surprise that the firm expeditiously added photography to the other methods already employed. More importantly, Colnaghi was among the first to recognize the artistic possibilities of the new medium and, accordingly, entered into an agreement with Julia Margaret Cameron for the sale of her photographs in 1863.
In 1894, Otto Gutekunst joined the Company and thus opened up an exciting and unique period in Colnaghi's history. Gutekunst entered into a close relationship with the young Bernard Berenson, and together, they began to form Mrs. Isabella Stewart Gardner's collection, now displayed in her 'Venetian palazzo' in Boston, pulling off coups and establishing record prices for Old Master Paintings in the process. Her greatest purchase was undoubtedly the Rape of Europa by Titian, now widely acknowledged as the finest Italian Renaissance painting in America. In July 1911, Gustavus Mayer joined Gutekunst, and the firm moved from the old premises at 13/14 Pall Mall East to the specially designed new building at 144/6 New Bond Street. Business increased still further, especially in the American market, as a result of a tacit agreement with the Knoedler Gallery in New York. Among numerous important sales during this period were the St. Francis of Assisi in Ecstasy by Giovanni Bellini and the Portrait of Pietro Aretino by Titian now in the Frick Collection, New York. In 1930, the decision of the Soviet Government to sell for cash a number of the greatest masterpieces of the Hermitage, led to one of the most sensational transactions in the history of the modern art market. In the beginning, the negotiations were conducted jointly by Matthiesen in Berlin, and Colnaghi in London. They were later joined in St. Petersburg by Knoedler from New York. The bulk of the pictures, including works by Raphael, Botticelli, Van Eyck, and Rubens, were acquired by Mr. Andrew Mellon, and thence by the National Gallery of Art, Washington D.C. The Rijksmuseum, Amsterdam, purchased two Rembrandts and another went to the National Gallery of Victoria in Melbourne. In the post-war period of severe currency restrictions, Colnaghi was able to acquire, in bulk, The Prince of Liechtenstein's vast collection of prints, a section at a time, between 1948 and 1931- It contained not only great rarities, but also innumerable original etchings and engravings by masters of all schools from the sixteenth to the early nineteenth centuries, the sales providing a valuable source of foreign currency to the beleaguered British economy. In 1954, Colnaghi purchased sixteen drawings by Durer from Prince Georges Lubomirski. At the same time, James Byam Shaw, who was the world's leading authority on Italian drawings, was directly involved with the formation of what is probably the most important private collection assembled in this country since the war, that of Count Antoine Seilern. Known as the Princes Gate Collection, it now forms an essential part of the Courtauld Institute Galleries and is installed in Somerset House, London.