[7] Regarding the ecclesiastical jurisdiction, during this century the new city depended on, the diocese of the Río de la Plata (in today's Paraguay), created by Pope Paul III on July 1, 1547 with seat in Asunción.

The major parish church was a modest construction with adobe and wood walls, had two towers that gave the current Avenida Rivadavia the former name of Calle de las Torres,[8] which in 1605 Governor Hernandarias ordered to demolish[9] for being too old and indecent.

[12] Neither the Cabildo, Justice and Regiment of the city lost heart and immediately chartered a ship to Paraguay to acquire and bring the necessary wood for the rebuilding of the temple.

When the third bishop of Buenos Aires, Friar Cristóbal de la Mancha y Velazco arrived at his see on October 6, 1641, he found the cathedral, if not in a ruinous state, at least very deteriorated.

In the person of the excellent governor Don José Martínez de Salazar, the bishop found someone who would collaborate in the construction of the temple not only with his influence, but even with money of his own.

But behold, a work with so many appearances of solidity, after seven years, because of the inferior quality of some materials used in its construction, began to show signs of its inevitable ruin.

Masella designed a majestic church, much larger than the previous structure, with a three-aisled nave covered with barrel vaulting and lateral chapels.

Starting in 1826, French architects Prosper Catelin and Pierre Benoit built a new Neoclassical façade for the cathedral inspired by the Palais Bourbon in Paris.

The façade of the building consists of a tall portico, inspired by Classical architecture, with twelve columns and a triangular pediment on top.

The scene represents the reunion of Joseph with his brothers and father Jacob in Egypt, and was intended as an allegory of the unity of the Argentine nation after several fratricide wars.

The Cathedral of Buenos Aires is a Latin cross building with transept and three-aisles with side chapels connected by corridors.

The most important is the main gilt wood altarpiece in Rococo style, dating from 1785 and executed by Spanish sculptor Isidro Lorea.

The two pulpits of the cathedral, in transitional Rococo-Neoclassical style, were created in 1789-1790 by the Spanish sculptor Juan Antonio Gaspar Hernández, who would later (1799) direct the first art school of Buenos Aires.

In 1880, the remains of General José de San Martín were brought from France and placed in a mausoleum, reachable from the right aisle of the church.

The black sarcophagus is guarded by three life-size female figures that represent Argentina, Chile and Peru, three of the regions freed by the General.

The mausoleum also has the remains of Generals Juan Gregorio de las Heras and Tomás Guido, as well as those of the Unknown Soldier of the Independence.