During the Texas Revolution, Dr. James Grant, a Scottish-born physician, and Francis W. Johnson recruited a volunteer army to invade Mexico and capture Matamoros, but after Sam Houston objected to the poorly organized venture, many recruits left before the expedition reached San Patricio along the Nueces River in January 1836. Mexican general Santa Anna, while organizing an army to attack Texan forces at the Alamo in San Antonio, learned of the plan and sent General Jose Urrea to stop it. Urrea's cavalry, reinforced with 300 infantrymen, crossed the Rio Grande on February 16. Grant and Johnson then split their troops to search for horses. Urrea attacked Johnson's camp at San Patricio on the morning of February 27, and Johnson and 4 others escaped while 18 Texans were killed and 32 captured. On March 2, Urrea's soldiers surprised Grant's company at Agua Dulce Creek, where Grant was among 12 Texans killed, 6 were taken prisoner, and 6 escaped, in a brief skirmish that occurred the same day the Texas Declaration of Independence was signed at Washington on the Brazos.