Thomas Smith Williamson inherited from his father a love for the study of God's Word, and a practical sympathy for the down-trodden and oppressed, which were ever the distinguishing characteristics of his life. He was also blessed with a godly mother and with five earnest-working Christian sisters, four of whom were older than himself. He was converted during his stay at Jefferson College, Cannonsburg, Pa., where he graduated in 1820. Soon after, he began reading medicine with his brother-in-law, Dr. William Wilson of West Union, Ohio, and, after a very full course of reading, considerable practical experience, and one course of lectures at Cincinnati, Ohio, completed his medical education at Yale, where he graduated in medicine in 1824. He settled at Ripley, Ohio, where he soon acquired an extensive practice, and April 10, 1827, was united in marriage with Margaret Poage, daughter of Col. James Poage, proprietor of the town. Perhaps no man was ever more blessed with a helpmeet more adapted to his wants than this lovely, quiet, systematic, cheerful, Christian wife, who for forty-five years of perfect harmony encouraged him in his labors. They thought themselves happily settled for life in their pleasant home, but God had better things in store for them. His Spirit began whispering in their ears the Macedonian cry. At first, they excused themselves on account of their little ones. They felt they could not take them among the Indians, that they owed a duty to them. They hesitated. God removed this obstacle in his own way--by taking the little ones home to himself. As this was a great trial, so was it a great blessing to these parents. This was one of God's means of so strengthening their faith that, having once decided to go, neither of them ever after for one moment regretted the decision, doubted that they were called of God to this work, or feared that their life-work would prove a failure. In the spring of 1833, Dr. Williamson placed himself under the care of the Chillicothe Presbytery, and commenced the study of theology. In August of that year he removed with his family to Walnut Hills, and connected himself with Lane Seminary. In April, 1834, in the First Presbyterian Church of Red Oak, he was licensed to preach by the Chillicothe Presbytery. Previous to his licensure, he had received from the American Board an appointment to proceed on an exploring tour among the Indians of the Upper Mississippi, with special reference to the Sacs and Foxes, but to collect what information he could in regard to the Sioux, Winnebagoes, and other Indians. Starting on this tour about the last of April, he went as far as Fort Snelling, and returned to Ohio in August. At Rock Island he met with some of the Sacs and Foxes, and at Prairie du Chien he first saw Dakotas, among others Mr. Joseph Renville of Lac-qui-parle. On the 18th of September he was ordained as a missionary by the Chillicothe Presbytery, in Union Church, Ross County, Ohio.