On 14 May, Lewis and Clark set off on their expedition to explore what is now the northwest of the United States. The trip had been ordered by President Thomas Jefferson.
Citation:
Editors. "The Lewis and Clark Expedition".
The Literary Encyclopedia. First published 01 February 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=4380, accessed 22 May 2013.]