After Santa Anna's victory in San Antonio, at the Alamo, he felt overconfident and split his army into five columns after one of his generals, José Urrea, defeated a Texan army in Goliad. Near San Jacinto, Santa Anna ordered his reduced column to rest, and his biggest mistake was not to order patrols or sentries posted while the whole army was resting and Sam Houston was planning a surprise attack that his troops would execute with little difficulty as no alarm of attack was sounded and the whole Mexican army got completely caught by surprise.
As of the Constitutional Convention of Texas of 1836, whose delegates were elected in February 1, 1836, its sense of urgency was brought about by the approach of the Mexican Army led by Santa Anna which would arrive in Texas a month later.
