George Caleb Bingham’s father-in-law, Reverend Robert Stewart Thomas (1805-1859), was “a tall man…above six feet in height, but a stoop… diminished his stature … His limbs were not fleshy, in fact, they were inclined to be lean – and though he was moderately strong, there was not the appearance of strength. His hair was rather short, without gray, moderately thick and hung down the side of his head, lank, black and oily…He was spoken of as a great scholar, a splendid logician, and a man of wide learning,” but he also a man with “kindliness of heart.”
He was born on June 25, 1805, in Scott County, Kentucky, to the state’s treasurer, John Pendleton Thomas (1761-1832), and to the former Lucy Thurston (1765-1816). Though raised as a Presbyterian, when he was 16, he chose to be a Baptist. Robert graduated from Transylvania University in 1823, and a year later from Yale, with a master’s degree. He was 19. He returned to Kentucky. That same year, in Bourbon County, he became a licensed Baptist preacher and married 15-year-old Elvira Johnston (1809-1871), a daughter of William Henry Johnston (1776-1850), a well-to-do planter and merchant, and his wife Rachel Spears (1787-1850). Elvira’s older sister, Elizabeth Keller Johnston (1802-1827), had also married at 15. Her husband was David McClanahan Hickman (1788-1851).
The Johnstons, Thomases, and Hickmans all moved to Boone County, Missouri, in 1827. There they socialized with the most successful planters in the region. By 1829, the gentlemen of Boone County wanted to assure a fine education for their sons without the expense of sending them east. Hickman spearheaded the movement. He founded a private school named for the region where it was located, Bonne Femme Academy. For headmaster, Hickman chose his brother-in-law. In the ten years that Dr. Thomas was in charge, “no academy in the West was more noted for scholarship nor graduated in proportion to the number of graduates a larger number of useful and able men.”
From Bonne Femme, Thomas moved to Columbia College, where he taught in the first years of the 1840s. In 1843, he became a professor of English Literature at the University of Missouri. Near the end of the decade, James Sidney Rollins, a state legislator and strong supporter of education, introduced a recently widowed friend, George Caleb Bingham, to Thomas’ eldest daughter, Eliza. While courting her, Bingham painted portraits of the Thomas family. The artist and Eliza Thomas married on December 2, 1849.
Baptist leaders recruited Thomas in 1852 to lead a Baptist college to be built near the western Missouri border in the town of Liberty, Missouri. The college would be named William Jewell College in honor of a major donor and respected church elder.
Thomas served as the first president of William Jewell from 1853 until 1855, when the school ran out of funds to pay faculty. The Kansas-Nebraska Act of 1854 had caused violence and economic losses at the western Missouri and eastern Kansas. caused violence and economic losses to the people of Liberty, Missouri, and surrounding areas. Paying tuition became a luxury. Dr. Thomas, his wife Elvira, “a fine, large, portly, pleasant lady,” and their children moved to Kansas City, Missouri, where he purchased a corner unit in McGee’s Addition, a new development of row houses south of town. Reverend Thomas became the first pastor of Kansas City’s first Baptist church. The church’s founders included Georg Bingham, and Lykins families. The head of the Lykins family was Johnston Lykins, a former Baptist missionary who had become a real estate developer. He was also a mayor Kansas City (1853-1854). His second wife, Matilda “Mattie” Livingston Lykins was a cousin of Thomas “Stonewall” Jackson. As the church grew, so did the friendship among the families. 
Thomas’ health was frail when he left William Jewell College. After his 22-year-old daughter, Sallie, died in early 1859, not only his physical, but his mental, health faltered. The religious scholar, who had fallen from a college presidency to a simple pastoral position, was admitted to the State Lunatic Asylum, where he died. The Glasgow Weekly Times reported:
Mr. Thomas, since our earliest recollection, has been engaged in the advancement of the educational interests of Missouri. A man of excellent education, vigorous intellect and sterling worth…As a speaker, he was plain, practical and convincing – as a debatant, he was pointed and logical. As a citizen, none enjoyed a higher reputation – as a father, few have governed with such leniency and yet with such success – as a man he was respected and beloved. 
Robert Stewart Thomas’s portrait by George Caleb Bingham disappeared from William Jewell College a few decades ago amid rumors of theft. The Missouri Artist’s likeness of his mother-in-law, Elvira Thomas, has been restored and hangs in a place of honor at William Jewell College in Liberty, Missouri. Perhaps someday the two portraits will be displayed together again.
 D. C. Allen, A Sketch of the Life of the Rev. Robert Stewart Thomas, A. M., First President of William Jewell College (Liberty, Missouri: 1909) 13 (Missouri Valley Room Special Collections MVSC 378.778 T46zaL, Kansas City Public Library).
 Ibid. Thomas was ordained in 1830.
 Ibid. Allen, op. cit.
 Ibid. Allen added an explanatory note: “though in Baptist literature he was and still is spoken of as Dr Thomas yet there is no evidence that he ever received the degree of DD. As a fact during his days in Missouri it would have been very difficult for a Baptist clergyman in this State no matter how elegant a scholar he may have been to have obtained the degree of DD.”
 Correspondence with archivist at Missouri Baptist Historical Society Archives, Partee Center, William Jewell College Liberty, Missouri
 “Death of Prof. Robt. S. Thomas,” The Glasgow Weekly Times, October 6, 1859, page 3, column 2.