Complex sentence: After the American Revolution and the ratification of the Constitution of the United States for the United States of America, the United States Treasury Department was placed in charge of managing all public lands; until 1812 when the General Land Office was created to assume that duty.
Split into simpler sentences: After the American Revolution and the ratification of the Constitution of the United States, the United States Treasury Department was placed in charge of managing all public lands. In 1812, the General Land Office was created to assume that duty.