The first two battles of the Mexican American War took place at Palo Alto and Resaca de la Palma on May 8th and 9th. The Mexican forces who were made their stand from defensive positions were forced to withdraw in both battles. The determination of American forces under General Taylor carried the day in both cases.
After the initial skirmish between American and Mexican forces Taylor moved most of his forces back to Point Isabel his supply base while leaving his most forward position Fort Taylor to be defended by 500 men. The Mexican began an artillery barrage against Ft Texas which was located opposite Matamoris on the Rio Grande. From Point Isabell the American forces could hear the cannon attack on Ft Texas and concerned mounted as to fate of her defenders. Samuel Walker a Texas ranger led four others through Mexican lines. He then managed to sneak into the fort. There, he determined that the Mexican assault had not harmed anyone. Walker successfully returned to American lines and reported.
On the seventh, replacement forces arrived at Point Isabell to defend the base, freeing Taylor to move out and relieve Fort Texas. The first afternoon the men moved out. They covered 5 miles that day and then camped out for the night. The Mexican army under General Arista decided to make their stand on a grassy plain spotted with ponds. Arista had 5,000 men, Taylor 3,000. Taylor allowed his men a last drink and headed toward the Mexican lines at 2:30 PM. The Mexicans opened fire first, but as the Americans were out of range the cannon balls fell harmlessly. Taylor then brought forth his artillery and it became an artillery duel between the two forces began. The American artillery was accurate and had a devastating effect on the Mexican forces. The Mexican tried a flanking attack on American position. The attack was successfully repulsed. The fighting continued until dusk with both sides sustaining casualties.
At dawn the Mexican forces withdrew towards Matmoras and Ft Texas. Taylors forces followed and found the Mexican forces dug in along an old bed of the Rio Grande called the Resaca de La Palma. This was an excellent defensive position and the Mexican were dug in well. The American forces tried to dislodge the Mexican with an artillery attack, but in that the American forces were not successful. A number of assaults took place against the Mexican lines. At first they were not successful, however American forces fought desperately, until finally forces under Captain Smith managed to capture a key Mexican cannon position. Then American forces managed to out flank Mexican forces on the right flank. By 5’o'clock Mexican lines broke and their soldiers fled across the Rio Grande.