Complex sentence: Lear attempted to help the Americans during the ensuing French embargo, however, with the Louisiana Purchase looming large for Jefferson, Lear was asked not to irritate the French commanders, and after a suggestion from James Madison left.
Split into simpler sentences: Lear attempted to help the Americans during the ensuing French embargo. However, with the Louisiana Purchase looming large for Jefferson, Lear was asked not to irritate the French commanders, and after a suggestion from James Madison left.