The Magistrate's House was built for Antonio Vicente Yánez, who in 1771 was appointed as Magistrate, or Alcalde Mayor of the town of El Escorial and the Royal Estate of San Lorenzo. He was in addition a member of His Majesty's Council, Magistrate for Crime of the Royal Chancery and Lawyer of the Royal Councils.
He was the first Magistrate to decide to live permanently in San Lorenzo, despite his obligation to live in El Escorial.
The building is from 1771 and the architect was Diego Ochoa, an assistant to Jaime Marquet in the Royal Coliseum. On 22 April 1773, Juan Esteban certified that the building work on the house had been finalized.
The floor shape is trapezoidal and externally the building is one of the most representative 18th century buildings in the town. Its most important facade looks on to calle Gobernador, where the entrance is found, with a moulded granite frame and lateral pilasters bearing two cantilevers which support a forged-iron balcony.