In the first part of his career Batoni was best known for his history paintings and he became one of the most refined practitioners of the Roman grand manner descending from Raphael (1483–1520) and the baroque classicism of Maratti (1625–1713). The climax of his career as a history painter was the Fall of Simon Magus (1746–55) painted for Saint Peter’s and today in Santa Maria degli Angeli. With its sparkling technique and sense of drama the painting is much less academic than others of the Maratti school. A later subject picture Alexander and the family of Darius (Potsdam) is more severe in its relief composition and accords well with the work of Mengs (1728–79) and other early neo-classical painters in Rome.
As a portraitist Batoni painted grandees from across Europe but his best clients were the British, who had more money than most. Some, like the Earl of Exeter, bought contemporary grand manner paintings and other antiquities, but most were casual collectors who went to Italy to have fun at moderate cost and acquire some educational polish which they could air back home. A portrait commissioned from Batoni at least proved they had some contact with the cultural life of Rome, beyond drinking, gambling and wenching. Many of his portraits are populated in the background by famous antiquities or architectural sites. Batoni was held to achieve a very good likeness and his portraits are far from formulaic, revealing, in a reticent and tasteful way, differing personalities and slight variations of status. The full lengths are among the most memorable, like the Earl of Northampton (Fitzwilliam Museum, Cambridge) standing by a bust of Minerva playing with a greyhound. Sir Wyndham Knatchbull-Wyndham (Los Angeles County Museum of Art) and the Earl of Leicester (Holkham) are dressed up in Van Dyck costume, in homage to much loved court painter of Charles I. The Scottish sitter Sir William Gordon (Fyvie Castle) stands flamboyant with kilt and sword like a highland chieftain though his kilt looks a bit too silky and Italian. More dignified is the group of Sir Watkin Wynn and Companions(National Museum of Wales, Cardiff) Sir Watkin owned great parts of Wales and was a patron of the arts. His companions do not defer to him, since though less important, they too are gentlemen and, in that respect, his equal. A sensitive and beguiling half length is the musical John Lord Brudenell in the Buccleuch collection. In his last portraits, like the Princess Giustiniani (Scottish National Gallery, Edinburgh), the looser and broader handling introduces a new intimacy and directness.