Between the years 1822 to 1824, Paul Wilhelm undertook his first major
research trip to Cuba and North America. He kept a diary in which he described the places he visited in great scientific and
ethnological detail. An artist produced numerous images of the landscapes, plants, and animals. Paul Wilhelm devoted himself particularly to the study of North and South America. He spent time exploring the western United States and met the son of
Sacagawea,
Jean Baptiste Charbonneau. After his initial meeting with Jean Baptiste Charbonneau in 1823 at the
Kansas River, likely arranged by
William Clark, Paul Wilhelm left camp and headed north with
Great Plains veteran
Toussaint Charbonneau, Jean Baptiste's father and Sacagawea's husband, hired as an interpreter. The Duke’s party spent five months in the upper Missouri country visiting trading forts,
Indian tribes, and collecting scientific data. Paul Wilhelm is traditionally included as one of the first explorers of the headwaters of the
Mississippi and
Missouri rivers. As late as the 1850s, he visited
Baron Ottomar von Behr, a German farmer and sheep breeder,
meteorologist, and scientist living in
Sisterdale, Texas. When he visited
New Braunfels on an 1855 visit, artist
Carl G. von Iwonski made him a gift of six pencil sketches of the artist's Texas work. ==Marriage and later life==