What pseudonym did the authors of the Federalist Papers use?

The authors of the Federalist Papers used the pseudonym Publius.

The Federalist Papers were a series of 85 essays published in 1787 and 1788 to support ratification of the proposed United States Constitution. Alexander Hamilton, James Madison, and John Jay wrote the essays, but all appeared under the shared name Publius. The name referred to Publius Valerius Publicola, an ancient Roman statesman associated with the early Roman Republic.

The pseudonym concealed the individual identities of the writers and presented the essays as a unified defense of the Constitution. Historians now identify authorship for nearly all of the essays, although a few were disputed between Hamilton and Madison. The papers remain an important guide to how leading Federalists explained federal power, checks and balances, and the proposed constitutional structure.