submitted designs for the Capitol; however the drawings were regarded as crude and amateurish, reflecting the level of architectural skill present in the United States at the time. The most promising of the submissions was by Stephen Hallet, a trained French architect. However, Hallet's designs were overly fancy, with too much French influence, and were deemed too costly. A late entry by amateur architect William Thornton was submitted on January 31, 1793, to much praise for its "Grandeur, Simplicity, and Beauty" by Washington, along with praise from Jefferson. Thornton was inspired by the east front of the Louvre, as well as the Paris Pantheon for the center portion of the design. Thornton's design was officially approved in a letter dated April 5, 1793, from Washington, and Thornton served as the first Architect of the Capitol (and later first Superintendent of the U.S. Patent and Trademark Office). In an effort to console Hallet, the commissioners appointed him to review Thornton's plans, develop cost estimates, and serve as superintendent of construction. Hallet proceeded to pick apart and make drastic changes to Thornton's design, which he saw as costly to build and problematic. In July 1793, Jefferson convened a five-member commission, bringing Hallet and Thornton together, along with James Hoban (winning architect of the "President's Palace") to address problems with and revise Thornton's plan. Hallet suggested changes to the floor plan, which could be fitted within the exterior design by Thornton. The revised plan was accepted, except that Secretary Jefferson and President Washington insisted on an open recess in the center of the East front, which was part of Thornton's original plan. The original design by Thornton was later modified by the British-American architects Benjamin Henry Latrobe Sr., and then Charles Bulfinch. The current cast-iron dome and the House's new southern extension and Senate new northern wing were designed by Thomas Ustick Walter and August Schoenborn, a German immigrant, in the 1850s, and were completed under the supervision of Edward Clark. Construction L'Enfant secured the lease of quarries at Wigginton Island and along Aquia Creek in Virginia for use in the foundations and outer walls of the Capitol in November 1791. Surveying was under way soon after the Jefferson conference plan for the Capitol was accepted. On September 18, 1793, President Washington, along with eight other Freemasons dressed in masonic regalia, laid the cornerstone, which was made by silversmith Caleb Bentley. Construction proceeded