Although the President and military officers returned to Washington only a few days after the British left, Congress did not return for three and a half weeks. The Thirteenth Congress officially convened on September 19, at the Blodgett's Hotel, one of the few surviving buildings large enough to hold all members. The Blodgett's Hotel also housed the U.S. Patent Office. Although the British had destroyed all public buildings, the Blodgett's Hotel and U.S. Patent Office were spared. It was in this building that Congress met between September and December 1815 (when construction of the Old Brick Capitol was complete).