Dr. James Grant the revolutionary leader, also known as Don Diego Grant, was born on July 28, 1793 in Scotland. In March 1825, he received a dual appointment as medical officer to the Real del Monte mining company and as physician to the British diplomatic mission in Mexico. During the next two years he appears to have undertaken clandestine visits to Texas on behalf of the British charge d’affairs and spymaster Henry Ward. This activity culminated in the Fredonian Rebellion of 1826–27, in part instigated as a British attempt to interpose a barrier to American immigration into Texas.
On September 25, 1830, he formally became a citizen of Mexico and was elected to the state legislature as one of the three deputies for the department of Parras. His involvement in politics saw him appointed secretary and eventually deputy president of the legislature by 1835 and won him the appointment of Jefe de Armas or colonel of militia. In that latter capacity he took the field against Gen. Martin Perfecto de Cos in April 1835, after the Centralistas set up a rival state legislature in Saltillo. On that occasion Cos backed down, but following General Santa Anna’s victory in Zacatecas the following month, Cos returned and on June 5 arrested both the president of the Federalist legislature, Augustín Viesca, and his deputy president, James Grant, as they tried to flee to Texas.
The remaining Federalist leaders set in motion plans for a “general revolutionizing” aimed at creating a breakaway republic of Northern Mexico. As part of this plan, the escape of Viesca and Grant was engineered in order that they could gather troops in Texas, where the colonists were already in open revolt and laying siege to General Cos at San Antonio de Bexar. Grant and a Colonel Gonzales accordingly rode to join the Texian insurgents at Bexar only to find the siege faltering and the army on the point of disintegration. According to John Durst, a deputy from Nacogdoches, Grant was responsible for persuading Ben Milam to make the famous appeal for volunteers to storm the town, and he was certainly elected one of the four colonels to lead the assault. Although badly wounded on the first day, he and Colonel Gonzales subsequently brokered the defection of most of Cos’s forces and so brought about his surrender on December 9, 1835.
Afterwards, with the aid of Col. Frank Johnson, Grant set about organizing an expedition to Matamoros to link up with his Federalist colleagues. Initially this expedition had the backing of the Texian General Council, and, as commander-in-chief, Gen. Sam Houston was accordingly instructed to take command. Unfortunately confusion ensued as operational command was successively offered to Frank Johnson and James Walker Fannin. In the meantime, relying on his own authority as deputy president of the former legislature and Jefe de Armas, Grant proclaimed himself acting commander-in-chief of what he called the Federal Volunteer Army. Sending off Colonel Gonzales and a prominent Tejano leader named Placido Benavides as an advance guard, he unilaterally marched from San Antonio on January 1, 1836. News of this move and accusations he had stripped the garrison of both men and supplies precipitated a violent split in the provisional government and its effective collapse at a critical time.
Houston quickly caught up with Grant and on January 21 persuaded four of his six companies to halt at Refugio. However, Grant and Frank Johnson pushed forward with the remainder first to San Patricio and then across the Rio Grande. They were also accompanied by a senior East India Company officer, Colonel Edwards, revealing the British government’s continued clandestine involvement. Over the next month they fought Mexicans and Comanches but failed to make substantive contact with Antonio Canales or any of the other Federalist leaders other than Benavides. Gonzales had already been surprised and defeated at Meier. Worse, Colonel Edwards was killed on February 20, and two days later Frank Johnson returned to San Patricio with part of the force, where he was surprised by Gen. José de Urrea in the early hours of February 27. Unaware of this disaster, Grant and the remainder of his men were heading north from Camargo on March 2, when they too were ambushed, this time at the battle of Agua Dulce Creek. Benavides and a handful of others escaped, but most were quickly killed or captured. Accounts of Grant’s death vary in detail but agree that after being pursued for some miles he surrendered and had dismounted only to be immediately stabbed in the back by a Mexican lancer.