The second paragraph down at the left entitled the History of Livingston County , page 246,

(and again on page 645 of the same book in the 4th paragraph down) mentions Morgan Payne's service in the Mexican American War.  This war occurs in southern Texas and Mexico in the years 1846 -1848.  The Gen. Taylor mentioned is Gen. Zacchary Taylor and indeed there was a battle for Monterey, Mexico in Sept of 1746.  For a general history of the War with Mexico see this web site:

http://www.lone-star.net/mall/texasinfo/mexicow.htm

 

Other websites on the subject can easily be found on the internet by using your search engine looking for the "Mexican American War 1846".

 

After the capture of Monterey  Morgan returned to Pontiac, Livingston Co., Illinois , to enlist further recruits for this war. It was probably on this trip "back home" that he was able to pursuade his nephew John Payne Jr., who lived near Danville, about 80 SE, to join him in the Texas/Mexican War.