Samuel Bryan (1759-1821) was a Pennsylvanian Anti-Federalist author, who wrote during the American Revolution. Historians generally ascribe to him the Letters of Centinel written under the pseudonym Centinel between 1787 and 1789. Centinel attacked the proposed Constitution of the United States as a document in the interests of the "well-born few". He was the son of George Bryan, a judge on the Pennsylvania Supreme Court and the principal Anti-Federalist in the state, to whom the essays were frequently attributed at the time they were written.
Centinel wrote three series of essays. The first eighteen numbers appeared in late 1787 and early 1788, and reflected the Anti-Federalist opposition to the Constitution. Letters XIX through XXIV were produced toward the end of 1788. By this time, the Constitution had been adopted, and these essays sought to sway the election of representatives to the new government. In 1789, a final series of 69 papers appeared regarding proposed amendments to the Constitution.
- Storing, Herbert J., ed. The Complete Anti-Federalist. Chicago: University of Chicago Press, 1969