Rosario, Republic of Argentina
January 11th, 1823

Carlos Maria de Alvear watched the opposing forces carefully as he prepared the defenses of the town. Ironically, he learned most of his military skills after leaving the Spanish Army. Specifically, he learned about the art of "trench warfare," the careful use of artillery and cavalry, and the importance of outmaneuvering his enemy from American and French books. The Spanish, despite being beaten badly by the French during the Second Coalition War, was slow to adapt to the changes in warfare, and the colonial troops in the Spanish Empire were kept in the dark about such changes. Additionally, the Argentinian officer studied the strategies used by Bolivar up in the north as well, as the Venezuelan managed to kick the Spanish out of New Granada with his superb skills and tactical ingenuity. All in all, Alvear considered himself a student of warfare, one that attempted to implement and utilize any advantages at hand.

Rosario was a small, sleepy town of three thousand inhabitants. But every Argentinan on the battlefield knew that this town would make or break their new republic. The Federal League, backed by the Portuguese and the British, overwhelmed them at every turn up to this point, mainly due to the difference in firepower. The soldiers of the Federal League were armed with modern breechloading rifles supplied by the British, called the "Nottingham Rifles." Not only that, but they also had artillery, something the Argentinians sorely lacked. And Alvear knew exactly why the British and Portuguese were suddenly friendly to their enemies in Montevideo. It wasn't a secret that the British were in a "friendly" competition with the United States and sought to counter their influence across the world. When Nicolas Rodriguez Pena, the first and current president of Argentina, threw in his lot with the Americans, none of the other powers (especially the Spanish and the British) were pleased. As a result, the British, pressuring the Portuguese, sowed discontent in the Eastern Provinces and gave them arms to rebel against Buenos Aires. By now, the Federal League controlled most of northern Argentina, and they were steadily advancing towards Buenos Aires.

Rosario was the only town that connected western Argentina with the eastern parts. If Rosario was lost, then so was the war.

Thankfully, the United States wasn't planning on abandoning Argentina to its fate. After all, while it wasn't a federal republic like the United States, it was still a republic (to some extent). It also helped that President Pena wasn't a complete idiot and adopted some modest reforms to appease their powerful friend in North America. President Crockett, the current American president, was usually reluctant in providing aid to foreign revolutionary groups. But since Argentina was a nation and the Federal League was being supplied by the British... He and the American Congress gave Argentina its blessings and shipped tons of military aid over (everything from weapons, to money).

As a result, General Alvear's men, numbering ten thousand men, were armed to the teeth with the best American weapons: Lee Rifles, a few dozen SIA Revolvers split between the officers and some of the NCOs, twelve 6-Pound Field Guns, six 12-Pound Howitzers, and even a few of prototypes of the "Sam Repeating Rifles." They were comfortably dug in the outskirts of the town, with layers of trenches and barbed wires to deter any direct charges. A battalion of cavalry awaited in the nearby woods, ready to smash the enemy from the side and cause chaos. And he had one more advantage up his sleeve...

Alvear was betting on his enemies being overconfident and walking into his trap. After all, the Republican Army had been on the retreat for nearly a year now and the opposing general in the Federal Army, one Fructuoso Rivera, was thirsting for a complete victory.

So the Argentinan general waited for the enemy to move closer. The Federal Army outnumbered him two to one, but he knew with his current defenses, his men would hold. And even turn this battle into a rout if they held for a while.

Federal artillery began to fire and pounded the entrenched Republicans, but Alvear was expecting this and had his men dig foxholes and sloped barriers within the trenches themselves. It was a risky move, as it could result in a few of his men tripping and falling during the battle, but it would be a move that his enemies would not expect. General Rivera was not an idiot and used similar tactics throughout the war (though Alvear suspected that it was due to the British advisors in the Federal ranks). However, Rivera wasn't flexible and lacked keen battlefield insight. If there was a sudden change of pace during a battle, he was slow to pick up on it. If his first wave of troops were decimated, he would push forward again with his superior numbers and "superior" weaponry. Rivera was also far too aggressive, which was good against an enemy that was routing constantly, but not against an enemy that was preparing to make its final stand behind waves of defenses.

So General Alvear needed Rivera to think that the Republican lines were weakening from the bombardment and create an enticing bait for the Federal Army to take.

After an hour of artillery fire (Alvear informed his artillery crews to hold off on firing until the Federal Army was closer), Alvear made his move.

An explosion cut through the center of the first trenches as the last rounds of artillery struck. From the Federal Army's point of view, it looked like the centerline was in complete ruins. Republican soldiers laid on the ground unmoving while a few others scattered to the second line of trenches. If Alvear had no idea what was going on, he would have assumed that a trap under the first line of trenches exploded due to the artillery fire and caused an accident. In reality, Alvear had evacuated the soldiers from the center part of the first line of trenches and exploded a few kilograms of dynamite underneath the trenches. The "unmoving soldiers" were actually alive and part of a special unit to surprise the enemy, while over three thousand soldiers remained within the untouched parts of the trenches.

Expectedly, Rivera's men charged forward and converged on the breach. Many of them stopped outside of the range of the entrenched Republican soldiers to fire off a volley towards the trench, forcing all the peekers to duck their heads. The Republican Army held their fire until the enemy was within "the kill zone."

"Fire!"

The eight artillery pieces under Alvear's disposal ripped open canister shots onto the enemy ranks. Rivera's army wasn't densely clustered, but the soldiers were close enough to one another to cause significant damage. In the trenches, and outside the trenches, Republican soldiers opened fire. The Federal Army, which was used to the Republicans using muskets, was caught by complete surprise as they were struck by infantry fire from five hundred yards away. However, the shock wore off and the Federal troops kept on marching forward to at least take the first set of trenches. They picked off a few of the Republicans outside of the trenches, but most of them managed to roll back into the holes safely.

From then on, it was a massacre. The Federal Army took heavy losses pushing into the first line, but the Republicans also took casualties from the accurate shots from the Nottingham Rifles. Within minutes, a good chunk of the Federal Army was within the trenches, engaging in close combat against the numerically inferior Republican Army.

That was when Alvear pulled out the remainders of his surprises.

A bugle blew and Rivera's cavalry battalion burst out of the woods, rushing towards the Federal Army that was still in the process of spilling into the trenches. That was not all. A group of Native Patagonians, consisting of the people of Ranquel and Boroanos, rushed out with melee weapons and firearms. In total, the Natives numbered around three thousand men. Some of them ran to flank the Federal Army, but most of them ran to fight General Rivera and the five thousand troops he held back to use at his disposal. They were ordered to hold off any Federal reinforcements from arriving and to cause as many casualties as possible. From what Alvear saw, he knew that Rivera was going to be unable to deliver his orders to the brunt of his army.

While this was happening, the men in the second line and third line of trenches rose to aid their allies. Numbering over six thousand, they were fresh and ready to take on their Federal opponents. Meanwhile, the three thousand men in the fourth trenches, Alvear's last set of reserves, moved into the second line of trenches and waited for their moment to charge.

They were not needed, as General Rivera was shot and killed by a Native fighter just three hours later. By the end of the day, the Federal Army was shattered. three thousand Federal soldiers were dead, along with nine thousand wounded. Over five thousand soldiers (discounting the wounded) and all the Federal artillery pieces on the battle site were captured, while a few thousand barely managed to escape. Meanwhile, the Republican Army suffered a thousand dead and three thousand wounded. It was the biggest victory in the Argentinan Liberation War and turned the tide of the war in Argentina's favor. Though, the war was not over...