Urquiza was a caudillo in the fullest sense: a soldier, a rancher of enormous wealth, a politician who served as President of the Argentine Confederation from 1854 to 1860. A man of that stature needed a seat to match, and between 1848 and 1858 the architect Pedro Fossati built him one. The result is a model of mid-19th-century Italian-Argentine design, its main floor wrapped around two large courtyards with thirty-eight rooms, a library, a chapel, a dining hall, and two watchtowers. Inside were Italian marbles, French mirrors, and gilded ceilings. The gardens were lined with busts of the men Urquiza measured himself against: Hernán Cortés, Napoleon, Alexander the Great, Julius Caesar. Ambition was the whole point.

The palace was not only grand; it was startlingly advanced. It became the first building in Argentina with a complete running-water system, fed through pipes that drew from the Gualeguaychú River two kilometers away. The detail that makes the achievement land is this: Buenos Aires, the nation's great port and capital, still had no such system in 1870. A rancher's house in the Entre Ríos countryside had plumbing the metropolis lacked. Water was not the only sign of consequence. The palace functioned as a stage for power, where foreign diplomats were received, treaties were signed, and the Apostolic Nuncio, generals, and politicians came to pay their respects to the master of the house.

Argentina's 19th century was a long, violent argument over how the country should be governed, and Urquiza had made enemies. On the night of 11 April 1870, a force of more than a hundred armed men loyal to the federal dissident Ricardo López Jordán stormed San José, shouting for the death of the man they called a tyrant. Urquiza fired back from a doorway and wounded one attacker before a bullet struck him in the face; stabbed repeatedly, he died in the arms of his wife and daughter, who had tried to shield him. The violence did not end at the palace gate. That same day, in nearby Concordia, two of his sons were hunted down and killed. It was a political assassination meant to erase a dynasty.

After the murder, the house passed out of its violent moment and into history. Urquiza's widow, Dolores Costa, consecrated the death chamber as an oratory, preserving the handprints rather than scrubbing them away, a decision that turned private grief into permanent memorial. In 1935, Argentina declared the Palacio San José a National Monument, and it became the Justo José de Urquiza Museum. Its archives hold a remarkable trove: historical documents, antiques, paintings of Urquiza's battles, even the manifests of ships that once docked at Concepción's port. The rooms are so well kept that visitors are often allowed only to look in from the threshold and photograph from outside, as if the house were still occupied by the life it lost.