Fannin became an agitator for the Texas Revolution and on August 20, 1835, was appointed by the Committee of Safety and Correspondence of Columbia to use his influence for the calling of the Consultation. On August 27 he wrote to a United States Army officer in Georgia requesting financial aid for the Texas cause and West Point officers to command the Texas army. In September Fannin became active in the volunteer army and subscribed money to an expedition to capture the Veracruzana, a Mexican ship at Copano; but the expedition did not materialize, and Fannin went to Gonzales, where, as captain of the Brazos Guards, he participated in the battle of Gonzales on October 2, 1835. On October 6 he was one of a committee urging Stephen F. Austin to bring all possible aid to Gonzales, and when Austin brought up the whole Texas army and moved toward Bexar, James Bowie and Fannin were sent as scouts to determine conditions between Gonzales and Bexar and to secure supplies. On October 27 Bowie and Fannin selected a campsite near Nuestra Señora de la Purísima Concepción de Acuña Mission and on October 28 led the Texas forces in the battle of Concepción.
On November 10 Fannin was ordered to cut a Mexican supply route between Laredo and San Antonio but returned to headquarters when he was not joined by a supporting force. On November 13 Sam Houston, commander in chief of the regular army, offered Fannin the position of inspector general, but Fannin received an honorable discharge from the volunteer army on November 22 and began an urgent campaign for a larger regular army. On December 5 the General Council, acting on Fannin's advice, established an auxiliary volunteer corps. Houston commissioned Fannin as a colonel in the regular army on December 7, and on December 10 the council ordered him to enlist reinforcements for the army and to contract for war supplies in the campaign against Bexar. Bexar had surrendered on December 9, so the accumulated supplies were used in the 1836 campaign.
Continuing as an agent of the provisional government, Fannin, on January 9, 1836, began recruiting volunteers for the Matamoros expedition. After Houston withdrew from the expedition, Fannin was elected colonel of the Provisional Regiment of Volunteers at Goliad on February 7 and from February 12 to March 12 acted as commander in chief of the army. When he learned that the Mexicans under José de Urrea had occupied Matamoros, Fannin went no further with plans for the expedition and fell back to strengthen defenses at Goliad. Other elements of the expedition, under James Grant and Francis W. Johnson, were destroyed by Urrea, who then proceeded to attack Goliad. On March 12 Fannin dispatched most of his force to aid Texans near Refugio. On March 14 he received Houston's order to retreat to Victoria, which rescinded a previous order to relieve the Alamo. Waiting for the forces under Amon B. King and William Ward to return from Refugio, Fannin delayed retreating until he heard of their capture. On March 19 he began his retreat, but he and his men were surrounded and forced to surrender at the battle of Coleto. The Texans were imprisoned by the Mexicans at Goliad and subsequently murdered by order of Antonio López de Santa Anna on March 27, 1836. Fannin, because he was wounded, was shot separately at the mission on the same day.
In the months leading up to the Goliad Massacre, Fannin had shown defects as a commander. Accustomed to the discipline of a regular army, he adapted poorly to his situation as head of volunteers. He scorned the idea of electing officers and was disturbed by the lack of a clearly established hierarchy among his forces. His arrogance and ambition earned him the contempt of many of the men under his command. One private, J. G. Ferguson, wrote in a letter to his brother: "I am sorry to say that the majority of the soldiers don't like [Fannin]. For what cause I don't know whether it is because they think he has not the interest of the country at heart or that he wishes to become great without taking the proper steps to attain greatness." In his final weeks, Fannin wrote repeatedly asking to be relieved of his command. Most historians now agree that Fannin made many serious mistakes as a commander. But despite his reluctance to carry on and his sometimes poor military judgment, he held out bravely until the end. Fannin County was named in his honor, as were the town of Fannin in Goliad County and Camp Fannin, a United States Army installation.
28° 38.766, -097° 22.780
Fannin Memorial Monument