From legis.state.va.us:
As the model for Virginia's first permanent capitol, Thomas Jefferson selected the Maison Carrée at Nîmes in southern France, an exquisite temple which had been built by the Romans early in the Christian era. This building is the middle structure of our present capitol complex, its center rotunda area displaying the life-size Houdon statue of George Washington and portrait busts of the seven other Virginia-born presidents and of Lafayette, the French volunteer who fought for America and for Virginia during the American Revolution.
In 1904, extensive renovation and additional construction to the Capitol were begun. Wings were added to the west of the original structure as a new Senate chamber and to the east as new quarters for the House of Delegates. In 1964 connectors were enlarged on the wings to create conference room space. At the same time a modern heating and air conditioning system was installed. Other modernizations have also been added, including automatic elevators, public address systems, electronic voting tabulators, a snack bar, and other facilities unknown to Jefferson's contemporaries. These structures remain in use to the present day.