On Via Gregoriana, a road was opened to link the Spanish Steps to the Pincio garden park at the request of Pope Gregory XIII, to whom we owe also the current official calendar in most of the world. At number 30, just a few steps from the Church of the Trinità dei Monti, is one of the strangest facades of a building in Rome: Palazzo Zuccari.
Not many know that Baroque Mannerist painter and art historian, Federico Zuccari, bought the land in 1590 and built his studio and residence here in Rome in 1592. The building had later additions in the seventeenth century, transformations and adaptations in the eighteenth century and renovations in the early twentieth century. It was inspired by a visit to the Monsters Park of Bomarzo, the fairytale park built in the Lazio countryside near Viterbo. The artist in fact personally designed the doors and the windows in the shape of infernal mouths. Among these, the door on Via Gregoriana is a giant open mouth with the nose serving as the keystone of the house's entrance. This architectural choice, that was widely criticized but also greatly admired at the time, quickly earned the building the appellative of the House of Monsters.
At the time, the building did not go beyond the main floor, in which the same Zuccari frescoed several subjects among which La Gloria dell'Artista, where he portraited himself with his family. At his death in 1609, Zuccari wanted that the building become a residence for foreign artists but his heirs had to sell the palace to Marco Antonio Toscanella to pay off debts. This second owner raised the palace by adding two floors, probably entrusting the work to Girolamo Rainaldi.
From 1702, the building was rented to Maria Kasimira, widow of King John III Sobieski of Poland, who commissioned to Filippo Juvarra the construction of the small porch with columns on Piazza Trinità dei Monti. The building became an important cultural center of eighteenth century Rome. Then with the new owner Alessandro Nazzari the palace was turned into an inn for artists, which had among its guests Johann Joachim Winckelmann, who was Prefect of the Roman Antiquities from 1755 to 1768, and Louis David that painted here the Oath of the Horatii.
The house was divided into apartments until one of the tenants, a Jewish patron born in Cologne, Henriette Hertz in 1904, bought the whole building and subsequently carried out other works that incorporated the nearby palace. The house was an important cultural salon frequented by the poet and writer Gabriele D'Annunzio, who described it in his 1905 famous novel The Pleasure. Upon her death, Hertz left her collection of paintings to the Italian State, and were then exhibited at the Museum of Palazzo Venezia. The palace and its library were instead left to the German State with the aim of establishing a center for scholars and became the Hertzian Library, specialized in art books, with more than 160,000 volumes, accessible by special request.
The palace also houses important frescoes by Giulio Romano and is supported by 178 pillars of reinforced concrete because archeologists found the remains of an ancient garden of Lucullus in its foundations.