Urquiza's cavalry had broken the enemy. On both wings his horsemen had scattered the Buenos Aires squadrons and chased them across the creeks of the Pampas. Couriers were already writing dispatches headed "from the field of victory." And then Justo Jose de Urquiza, commander of the Confederation army, did the one thing no one could explain: he left. He marched off the battlefield with four thousand fresh reserves never committed, declined to return even after he learned his cavalry had won, and rode home to Entre Rios. His retreat on 17 September 1861 handed Bartolome Mitre the field at Pavon - and with it, the future shape of Argentina.
For most of the nineteenth century, Argentina was less a nation than an argument. Buenos Aires, rich from its port and customs, wanted the provinces left autonomous so no federal capital could siphon away its revenue. The interior provinces wanted exactly the opposite - a country centralized around Buenos Aires, sharing in its wealth. After the fall of Rosas in 1852, the quarrel hardened into two rival states: the Argentine Confederation, based in the interior, and the breakaway State of Buenos Aires. They had clashed before, at Cepeda in 1859, and patched things up with the Pact of San Jose de Flores, which set the terms for Buenos Aires to rejoin the fold. The peace did not hold, and Pavon would be where the long argument was finally decided by force of arms.
A tangle of disputed elections and assassinated provincial governors pushed the two sides back to war. President Santiago Derqui named Urquiza, the Confederation's most formidable general, to bring the rebellious province to heel; in Buenos Aires, Governor Mitre took command of the provincial army. On paper the Confederation was stronger - about 17,000 men against Mitre's 15,000, with a decisive edge in cavalry. Mitre's advantage lay elsewhere: better-trained infantry and 35 artillery pieces, supplied by Britain and worked by trained British gun crews. The armies finally met by the Pavon creek, some 40 km south of Rosario and around 260 km northwest of Buenos Aires.
The fighting lasted barely two hours. Urquiza had drawn an extended line east of the Domingo Palacios ranch, cavalry on the wings, and as Mitre's infantry advanced to within 800 meters, the Confederation guns tore into them - the Buenos Aires soldiers easy marks in their bright uniforms. On the flanks, Urquiza's horsemen did their work brilliantly: the left wing under Juan Saa and the renegade Ricardo Lopez Jordan shattered the porteno First Cavalry and drove it past the Arroyo del Medio, the very creek that divided the two provinces. But the Confederation center - untrained militia from the interior - buckled against Mitre's disciplined battalions and fell back.
Seeing his center give way, Urquiza abandoned the field and rode for Rosario, never spending the four thousand reserves still in hand. Word reached him on the road that his cavalry had triumphed. He did not turn back. Historians have argued about his reasons ever since - exhaustion, distrust of President Derqui, a secret understanding with Mitre, even a quiet calculation that holding national power was simply not worth risking his fortune and his grip on Entre Rios. The puzzle has never been settled, and Argentine writers still call it, plainly, the mystery of Pavon. What followed was not in doubt. Derqui resigned and fled to Montevideo; the vice president declared the national government dissolved; Mitre's influence spread across the country as federalist governors fell one by one. Elections barred from federalist candidates made Mitre the first president of a unified Argentine Republic - the capital back in Buenos Aires, its dominance unbroken.
The Pavon battlefield lies near 33.25 S, 60.22 W, by the Pavon creek in southern Santa Fe Province, about 40 km south of Rosario and a short distance inland from the Parana River. From altitude the country is flat Pampas farmland, threaded by small creeks running east toward the Parana - among them the Arroyo del Medio, the historic boundary between Santa Fe and Buenos Aires provinces. The nearest major airport is Rosario - Islas Malvinas International (ICAO SAAR, IATA ROS), roughly 40 km to the north. Buenos Aires - Aeroparque (SABE) and Ezeiza (SAEZ) - lies about 230 km to the southeast. The plain reads best from 3,000 to 4,500 feet on a clear day, when the creek lines stand out as ribbons of green against the cropland.