Mary Louisa was the daughter of Adelaide Thomason Talbot [1799/1800-1873] and Isham Talbot. Adelaide was the daughter of James B. Thomason, who was in turn the step-brother of William Thornton (1749-1828). Thornton is best known for his architectural designs, notably that of the US Capitol (1793). Portraits of William Thornton and his wife, Anna Maria Brodeau Thornton (d. 1865) were inherited by Mary Louisa and are now in the collection of the NGA (1942.8.25 and 1942.8.26). Adelaide became the third wife of Isham Talbot, US Senator from Kentucky in 1815-1819 and 1820-1825. [Compiled from sources and references recorded on CMS]
Bibliography
1995
Miles, Ellen G. American Paintings of the Eighteenth Century. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1995: 243, n.1