Homer Mattfield was a member of the Mexican Senate who was appointed to the Mexico Tribunal. As Chief Judge of the Tribunal, Mattfield presided over the Chapultepec treason trials, the trials of 8000 black slaves who joined the invading French army during the Hundred Day War.
Judge Mattfield announced on December 20, 1915 that a final verdict would be handed down by the Tribunal on January 5, 1916. However, the verdict was never announced, as the slaves were all freed when the Federal Prison in Chapultepec was stormed by members of the Friends of Black Mexico on January 4.