The main purpose of the Federalist Papers in American history was to advocate for the ratification of the U.S. Constitution. Written by key figures like Alexander Hamilton, James Madison, and John Jay, these essays aimed to explain the necessity of a strong central government. They addressed concerns about federal power and state sovereignty, arguing that a balanced government structure was essential for maintaining liberty and preventing factionalism. The papers helped shape foundational political thought, impacting the framing of American democracy.