In the last few years before the outbreak of the Civil War, another war stalked the borderlands of the Rio Grande Valley, this one between Mexico and Texas, personified by a reckless young Mexican grandee named Juan Nepomunceno Cortina. He was the ‘black sheep’ son of a large and wealthy family with considerable holdings on either side of the border; a handsome, dashing and impulsive man, quick to take offense at insult. For a number of reasons, most to do with his family wealth and influence, he was also seen as the champion of the poorer Mexican residents, who were not infrequently stung by Anglo contempt and injustice. For his own part, Cortina violently resented certain Anglo ranchers, including one Augustus Glavaecke, who had often accused Cortina of helping himself to his and other Anglo rancher’s livestock.
In spite of this, in 1858, Cortina was living at one of the family properties near Brownsville – close enough that he rode into town every day and whiled away the morning at a popular local coffee shop, drinking coffee and reading the newspapers. But one mid-June day, a former employee of his – Tomas Cabrera was drunk and disorderly, disrupting the peace and quiet of the coffee shop. Robert Spears, the city marshal, tried to arrest Cabrera, over the objections of Cortina. Spears answered Cortina with an insult, whereupon Cortina whipped out his pistol and shot Spears in the shoulder. He then grabbed his horse, pulling Cabrera up behind him, and galloped out of town. It was a spectacularly theatrical exit, and made him even more popular than ever among the poorer Mexicans along the border.
Cortina lay low at the ranch for some month, while those Anglo residents of Brownsville – especially those who entertained lively suspicions about him – wondered what he would get up to next. He was buying horses and recruiting men for some purpose, probably nefarious. It didn’t come clear until the end of September, the morning after a grand ball in Matamoros, which practically everyone of means, Anglo and Mexican had attended. In the wee hours of the morning, Cortina rode into town with a hundred of his mounted, well-armed new best friends, and took it over, lock, stock and both barrels. He was after a number of his bitterest enemies, rancher Glavaecke and Marshal Spears among them. They escaped, but three other Americans and a Mexican who tried to shield one of the Americans died at the hands of Cortina’s men. They broke into the jail, liberating about a dozen prisoners, but murdering the jailor. They also tried to hoist the Mexican flag over the deserted American compound of Fort Brown.