May 14, 1880 the Chiricahua Apache lead by Beduiat aka "Victorio" attacked Fort Santiago on the Gila. On the evening of the 14th the Apache warriors attacked a soldier and a citizen who were standing outside of the fort, though using arrows to maintain silence the men yelled and roused the troops. As townsfolk poured into the fort for protection the Imperials were able to mount canon and fire upon the Apache, breaking the coordination of the mounted natives and giving the soldiers more time to make ready.
Switching to repeater rifles, the Apache continued the assault, killing civilians and soldiers alike as they fled into the fort for safety. However, they were unable to break through and into the fort before the gates closed. They continued the assault until dawn but the Imperials were able to hold them off, and even made a daring rescue of a herd of cattle under cover of canon fire.
The Republic of Texas denies any involvement in the raid, stating that the Chiricahua are acting of there own accord. However, the presence of repeater rifles indicates it is likely that if they are not fighting on behalf of the republic, they are at a minimum being armed by the Texians.