At his post were born North Dakota's first two children of other than Indian parentage. The first, the daughter of Pierre Bonza, Henry's Negro servant, who had formerly been a slave in the West Indies, was born March 12, 1802. The first white child was born December 29, 1807, to the "Orkney Lad", a woman who had worked at the post for several years in the guise of a man, until the birth of the child betrayed her sex. Abandoned by the father of the child, John Scart, she remained at the post until a collection was taken up and she and the baby sent back to her home in the Orkney Islands. President Jefferson for some time had been eager to have a party explore the Missouri, cross the Rockies and reach the Pacific. In 1803 the Louisiana Purchase facilitated completion of his plans, and his secretary, Capt. Meriwether Lewis, with a friend, Capt. William Clark, started out on the journey of exploration. On October 13, 1804, the expedition came up the Missouri River into what is now North Dakota. Near the present site of Stanton, where the Knife River joins the Missouri, Lewis and Clark discovered villages of the Mandans and Hidatsa. Having been well received, they decided to establish winter quarters. Fort Mandan was built and the flag of the United States of America raised for the first time on North Dakota soil. It was here that the explorers secured the services of Charbonneau, the French interpreter, and his wife Sakakawea, the Shoshone Indian girl who guided them successfully through the Rockies to the Pacific (_see_ BISMARCK). After spending the winter with the friendly Indians, the expedition in April 1805 set out along the river again, following its course into Montana. Their journey through the mountains to the Pacific, led by Sakakawea, is one of the most thrilling adventures in American history. The party returned in September 1806 to the Hidatsa village on the Missouri where Lewis and Clark, taking leave of their faithful guide, set out for St. Louis and home. The careful observations recorded in the journals of their party are a valuable contribution to the history of this region.