The Civil War skirmish known as the battle of the Nueces took place on the morning of August 10, 1862, when a force of Hill Country Unionists, encamped en route to Mexico on the west bank of the Nueces River about twenty miles from Fort Clark in present-day Kinney County, were attacked by mounted Confederate soldiers. The Unionists, mostly German intellectuals led by Maj. Fritz Tegener, had camped without choosing a defensive position or posting a strong guard. The ninety-four Confederates, led by Lt. C. D. McRae, came upon the camp on the afternoon of August 9. Firing began an hour before sunlight the next morning; nineteen of the sixty-one to sixty-eight Unionists were killed, and nine were wounded. The nine wounded were executed a few hours after the battle. Two Confederates were killed and eighteen wounded, including McRae. Of the Unionists who escaped from the battle, eight were killed by Confederates on October 18, 1862, while trying to cross into Mexico, eleven reached home, and most of the others escaped temporarily to Mexico or to California. Some of the survivors, who included John W. Sansom and German members of the Union League from the area around Comfort, a militia organized to protect parts of Kendall, Gillespie, and Kerr counties from Indian raids and Confederate actions, eventually joined Unionist forces headquartered in New Orleans.
Among the conflicting contemporary and eye-witness accounts, the version published in 1905 by the military professional Sansom appears to be the most reliable and complete. Other accounts vary as to the number of men involved in the fighting and the number of casualties. Contentions over the event remained on both sides, with Confederates regarding it as a military action against insurrectionists while many German Hill Country residents viewed the event as a massacre. After the war the remains of the Unionists killed at the battle site were gathered and interred at Comfort, where a monument commemorates the Germans and one Hispanic killed in the battle and subsequent actions. The dedication of the Treue der Union monument occurred on August 10, 1866. To commemorate the 130th anniversary of the memorial, the monument was rededicated on August 10, 1996. It is the only German-language monument to the Union in the South where the remains of those killed in battle are buried, and where an 1866 thirty-six star American flag flies at half-staff.