The Library of Congress was established by an act of Congress in 1800 when President John Adams signed a bill providing for the transfer of the seat of government from Philadelphia to the new capital city of Washington. The legislation described a reference library for Congress only, containing "such books as may be necessary for the use of Congress -- and for putting up a suitable apartment for containing them therein...."
Established with $5,000 appropriated by the legislation, it was housed in the new Capitol until August 1814, when invading British troops set fire to the Capitol Building, burning and pillaging the contents of the small library.
Within a month, retired President Thomas Jefferson offered his personal library as a replacement. Jefferson had spent 50 years accumulating books, "putting by everything which related to America, and indeed whatever was rare and valuable in every science"; his library was considered to be one of the finest in the United States.