Complex sentence: In anticipation of the annexation of the Republic of Texas, which had established independence in 1836, Taylor was sent in April 1844 to Fort Jesup in Louisiana, and ordered to guard against attempts by Mexico to reclaim the territory.
Split into simpler sentences: In anticipation of the annexation of the Republic of Texas, which had established independence in 1836, Taylor was sent in April 1844 to Fort Jesup in Louisiana. He was ordered to guard against any attempts by Mexico to reclaim the territory.