William Lattimore was born in Norfolk, Virginia, in 1774 and later moved to Natchez, Mississippi Territory, where he practiced medicine. He played a pivotal role in the organization of the Mississippi Territory's government and served as a Delegate to the 8th and 9th Congresses, as well as the 13th and 14th Congresses. Lattimore also participated in the first State constitutional convention of Mississippi and held positions such as censor of the medical profession and commissioner for selecting the site of the new State government.