American agents... are the only persons authorized to hold councils of a political nature.

He was promoted to colonel in 1812. Walker transcribed and translated Pike's confiscated documents including his journal. Pike married Clarissa Harlow Brown in 1801.

As a United States Army captain in 1806–1807 he led the Pike Expedition to explore and document the southern portion of the Louisiana Purchase and to find the headwaters of the Red River during which he recorded the discovery of what later was called Pikes Peak. In 1810 Pike publiZebulon Piked an account of his expeditions a book so popular that it was translated into French German and Dutch for publication in Europe.