Located in the park on the Ilm, the Roman House was the favorite residence and retreat of Duke Carl August of Saxe-Weimar and Eisenach. The country and garden house with a view of the Ilm valley was built between 1792 and 1797 and was modeled on Roman villas under the direction of Goethe. It is regarded as a classicist "model house" for Goethe's architectural theories against the backdrop of his trip to Italy.

Ancient influences are also reflected in the interior of the imposing building. Apollo with the muses and Pegasus are at the center of the wall and ceiling paintings. A tour leads through the imposing entrance hall, which was also used as a dining room, the Blue Salon, once the scene of festive conviviality, and the Yellow Salon, the Duke's former study. In the adjoining rooms, where the bedchamber and dressing room were located, there are panels on the history of the house and sketches of the interior design. A permanent exhibition in the basement shows the development of the park on the Ilm since the late 18th century.

Since the thorough restoration of the Roman House in 1999, an unobstructed view of the neoclassical interior decoration has been available. As the original furnishings were lost, all furniture was removed. A fortunate exception: since 2014, the original portrait of Duchess Anna Amalia by Angelika Kauffmann has been on permanent loan from HRH Prince Michael of Saxe-Weimar-Eisenach and has been restored to the original furnishings of the house. Carl August had designated the painting, which was painted in Rome in 1788/89, as the programmatic room decoration of the Blue Salon.

The Roman House is part of the UNESCO World Heritage Site "Classical Weimar", which is a unique testimony to the cultural epoch of Weimar Classicism and reflects Weimar's outstanding role as an intellectual center in the late 18th and early 19th centuries.