Latrobe designed the Hall of Representatives with the intention of showcasing six large allegorical sculptures. They'd be carved by his lead "figural" stone carver, Giuseppi Franzoni. The other lead sculptor, Giovanni Andrei, handled the decorative and vegetative elements. Latrobe's initial sketch for a "figure of Liberty" appears in his east-west section drawing of 1805 at the very small scale of 1/8". But with a very fine touch in his drawings, even at a size of one and a half inches, Latrobe imparted many intentions of his idea for Liberty: her personification, her dress and hair, her accoutrements. Latrobe clearly draws and writes of a beautiful Greek style figure. Between 1805 and 1808 many letters discuss the progress and the changes of the monumental Sitting Liberty, including it's final height, it's posture, the position of each arm, its allegorical elements, and the eagle in repose that stood with Liberty. It's very clear that Latrobe was directing the artist, and although the work was coming from Franzoni's hand, it demonstrates a collaborative effort.
The Sitting Liberty was placed on its plinth in 1807 as a full scale plaster. It was to be carved in Vermont White Marble, but the Capitol burned before that could happen. The plaster statue was completely destroyed.
Not until Thomas Crawford's Statue of Freedom was raised in 1863, did the U.S. again have a monumental figure of Liberty on display.
My interpretation of the lost Sitting Liberty of 1807-1814 is based on the study of Latrobe's drawing, his letters, and his well-documented aesthetic opinions of the leading neo-classical sculptors of the day. His favorite sculptor was Englishman John Flaxman, and the first step in creating this piece was to offer the commission to Antonio Canova, then living in Rome. Canova had ten years worth of commissions ahead of him and declined the offer. Flaxman's student Franzoni was later hired to execute the work for Latrobe in America.
Another allegorical element for the Hall was a great American eagle in the frieze above the Speaker. Again, a small scale drawing exists of the eagle, and a preliminary sketch of it appears in a letter to Charles Willson Peale. Latrobe wrote to Peale asking for a drawing of an American eagle for Franzoni's use as a model. Franzoni's early forays had produced a distinctly European bird of prey, and Latrobe wanted him to see the American variety. Peale shipped Latrobe a whole eagle's carcass from his museum for him to work with. Latrobe also stated that the eagle was to be carved in alto relief. By sculpting my own interpretation of it, I understand the alto relief requirement as a way of maintaining reasonable proportions. The eagle appears twice in post-fire drawings by both Latrobe and Andrei. Latrobe lauded the eagle's grandeur and magnificence in a letter from 1807, and mentioned its final dimension: twelve foot six inches tip to tip.