Early in 1778, the Commonwealth of Virginia authorized George Rogers Clark to lead an expedition to protect American settlers in Kentucky and gave him secret instructions also to take Kaskaskia, an outpost on the Mississippi. With about 175 men, he floated down the Ohio to the falls at Louisville, proceeded to the present site of Fort Massac, and marched overland to Kaskaskia. Receiving word of the French-American alliance, the inhabitants of Kaskaskia welcomed Clark.
Clark continued his expedition by crossing what is now southern Illinois to the French outpost at Vincennes, just across the Wabash River in what is now Indiana. By taking Vincennes without resistance, Clark curtailed British plans to use the native population of the area to resist American expansion.
This collection contains the oath, which is dated July 20, 1778, and signed by 181 inhabitants, "to renounce all fidelity to George the Third, King of Britain, and to his successors, and to be faithful and true subjects of the Republic of Virginia as a free and independent state."
For the text, translation, and commentary on this document, see Clarence Walworth Alvord, "The Oath of Vincennes," Transactions of the Illinois State Historical Society for the Year 1907 (1908), 270-76 [977.3 IL65 1907]; James Alton James, George Rogers Clark Papers, 1771-1781, Collections of the Illinois State Historical Library, (Springfield, 1912), 56-59 [977IL6, v.8]; and Anton J. Pregaldin, "The Vincennes Oath, July 20, 1778," in Kathrine Wagner Seineke, The George Rogers Clark Adventure in the Illinois (1981), 589-618 [973.3 Se44g].