The Founding Fathers of the United States of America were political leaders and statesmen who participated in the American Revolution by signing the United States Declaration of Independence, taking part in the American Revolutionary War, and establishing the United States Constitution. Within the large group known as the "Founding Fathers", there are two key subsets: the Signers of the Declaration of Independence (who signed the United States Declaration of Independence in 1776) and the Framers of the Constitution (who were delegates to the Constitutional Convention and took part in framing or drafting the proposed Constitution of the United States). A further subset is the group that signed the Articles of Confederation. Many of the Founding Fathers owned African American slaves and the Constitution adopted in 1787 sanctioned the system of slavery.  The Founding Fathers made successful efforts to contain or limit slavery throughout the United States and territories, including banning slavery in the Northwest Ordinance of 1787, and abolishing the international slave trade in 1807. Some historians define the "Founding Fathers" to mean a larger group, including not only the Signers and the Framers but also all those who, whether as politicians, jurists, statesmen, soldiers, diplomats, or ordinary citizens, took part in winning American independence and creating the United States of America. Historian Richard B. Morris in 1973 identified the following seven figures as the key Founding Fathers: John Adams, Benjamin Franklin, Alexander Hamilton, John Jay, Thomas Jefferson, James Madison, and George Washington. Warren G. Harding, then a Republican Senator from Ohio, coined the phrase "Founding Fathers" in his keynote address to the 1916 Republican National Convention. He used it several times thereafter, most prominently in his 1921 inaugural address as President of the United States.