McClellan's first assignment was with a company of engineers formed at West Point, but he quickly received orders to sail for the Mexican War. He arrived near the mouth of the Rio Grande in October 1846, well prepared for action with a double-barreled shotgun, two pistols, a saber, a dress sword, and a Bowie knife. He complained that he had arrived too late to take any part in the American victory at Monterrey in September. During a temporary armistice in which the forces of Gen. Zachary Taylor awaited action, McClellan was stricken with dysentery and malaria, which kept him in the hospital for nearly a month. Malaria would recur in later years; he called it his "Mexican disease." He served as an engineering officer during the war, was frequently subject to enemy fire, and was appointed a brevet first lieutenant for his services at Contreras and Churubusco and to captain for his service at Chapultepec. He performed reconnaissance missions for Maj. Gen. Winfield Scott, a close friend of McClellan's father.