The maps of New Spain by Alexander von Humboldt and Zebulon Montgomery Pike
Cartographica Helvetica 47 (2013) 3–10
When Alexander von Humboldt (1769–1859) visited the United States of America after his expedition in South America (1791 to 1804), this young republic showed great interest in the German naturalist and especially in his information about the Spanish colony of Mexico. At that time the exact boundary line between New Spain and the recently acquired Louisiana Purchase were not even known to President Thomas Jefferson. Humboldt's draft of a map of Mexico, which he had left to Albert Gallatin, Secretary of the Treasury, eventually led to resentment. In 1810, Zebulon M. Pike (1779–1813), American explorer and military officer, published a travelogue and the Map of The Internal Provinces of New Spain of his expedition through central and western Louisiana. Pike's map was undoubtedly based on a copy of Humboldt's map. There was no reference to this in the corresponding text, hence Humboldt accused Pike of plagiarism for the rest of his life.