Peter M. Mercer, soldier in the Texas Revolution and early settler, was born in Georgia on December 25, 1807, to William and Isabella (Maloy) Mercer. He moved to Texas in 1835 as a volunteer in the Texas army. He was living at Washington-on-the-Brazos when Texas independence was declared and was co-owner of the building in which the constitutional convention was held. Mercer was placed under the command of James W. Fannin, Jr., but managed to escape the Goliad Massacre; he later fought with Sam Houston at San Jacinto. After the war he settled on the San Gabriel River in Milam County. He married a woman called Aunt Celie by family members; the couple had no children. Mercer was killed by Indians on June 17, 1844, and was buried in Locklin Cemetery at San Gabriel, not far from where he was killed.