The walls of many buildings, during many other periods, were covered with color, if not with monumental sculpture, often polychrome. One only has to look at the façade of Santa María de Olite or the mural paintings of the Gothic period to realize that nothing could be further from the stark stone that many factories show today as a result of unfortunate interventions. During the Renaissance, the interiors of churches and palace complexes also had coverings, as a true epidermis of an architectural concept.

The Baroque centuries witnessed a special presence of color, ornamentation, ostentation and magnificence in exteriors and, even more so, in the interiors of churches, chapels and chapels, which wanted to generate an authentic "caelum in terris". It was the moment of the triumph of plasterwork and decorative and illusionist painting. As for the temporality of one system or the other, it should be noted that, from the second decade of the 18th century, the large painted scenographies were coexisting with the plasterwork, which would come to replace them decades later. This "skin of the architecture", as Professor Alfredo Morales put it for the case of Seville, constitutes the true essence for the understanding of the interior space of the temple, in order to motivate the senses of the faithful, always more vulnerable than the intellect, in a mostly illiterate society.

Under these assumptions, we will focus on three aspects of the basilica of San Gregorio Ostiense, located on the top and, therefore, visible symbol of dominion of the landscape and nature controlled by man, with a careful design in its striking and sought after silhouette.

At the end of the 17th century, in 1694, with the opportune episcopal licence of 1691, the master from Estella, Vicente Frías, was commissioned to make the monumental façade of the basilica, which he left unfinished at his death in 1703. The one in charge of finishing it, between 1710 and 1712, was another famous retablist, in this case from Tudela, José de San Juan y Martín. His work gave the ensemble the quality and the air of a work from the focus of Tudela, with his contribution staff. In order to enhance the ornamentation, he used stucco, more moldable than stone, contrary to what was stipulated. The appraisers were José Ortega, on behalf of the basilica, and Juan Angel Nagusia on behalf of San Juan. Both masters denounced that certain areas were carved in stucco when "it was of obligation of said Joseph of San Juan to execute in stone all that is expressed" and in addition "it is to the inclemency of the sun, air and water". However, they also recognized that if "the said ornaments and stories had been executed in the reliefs that the said stone work had, it could not be as perfect and beautiful as it is because it was made with the said stucco subject ".

The stone chosen was white, possibly from the quarries of Mendaza, to stand out from the rest of the buildings in the area that use reddish stone. The model was a facade of three streets, the lateral ones flat and of lesser height, joined to the central one by means of aletones. The latter has the peculiarity of being organized like a shell altarpiece, with a dynamic floor plan, elevations with sotabanco, bank, two bodies articulated by Solomonic columns and an attic in the shape of an orange average .

A large part of its surfaces supported a profuse ornamentation, or what is a real disguise that hides the Structures. Unfortunately, much of that decoration, mainly the vegetal motifs and the two historiated reliefs, disappeared in the last century.

source Regarding the Solomonic columns, with a garland in their throats, it is possible that they were inspired by Juan Caramuel's treatise on oblique architecture (1678), which contributed so much to the baroque style of the Hispanic altarpiece. They were used in Navarre on a few occasions, such as the altarpiece of Santa Catalina in the cathedral of Pamplona (1686) or the engraving representing the Courts of Navarre, signed by Dionisio de Ollo (1686).

The iconography presents Saints Peter and Paul on the sides of the coat of arms with the episcopal attributes in the first body. The second body is presided over by the figure of the titular saint with two reliefs that are now lost and that we can identify thanks to old photographs. The one on the left represents the moment before the death of the saint in his bed in Logroño, when he got up and blessed his disciples. The compartment on the left was reserved for the arrival of the cavalry with the coffin of the saint to the mountain of Piñava, where there was already a small church and a hermit who, reclining, attends the scene. Father Andrés de Salazar describes this passage in the eighteenth chapter of his work (1624) when he states: "and the same thing the third time, which came to be near where the church and basilica of this most glorious saint is now, which is on the summit and cima of a mountain not very high, although in some parts it is fragrant ..... When the holy body arrived there, a Shrine of Our Lady of Fair Love orchurch called San Salvador de Piñava was already founded ... In this church there lived a very holy man living a hermit life, who with the devout people of the land and with those of the blessed family of San Gregorio placed his most holy body, no doubt, among other countless relics of holy martyrs that were there .....".

In the shell there was a large relief of the Assumption of the Virgin, visible in Madrazo's work, published in 1886, although it no longer appears in the 1916 photograph. In its general lines it followed the model of the Assumptionist group of the main altarpiece of Miranda de Arga, work of the aforementioned José de San Juan (1700-1704).

As is well known, the peninsular trip of the Santa Cabeza in 1756, at the royal request, to fight against a great plague of locusts, made possible the construction of the new chancel and its decoration according to the rococo style.

Given the importance and significance of project, plans were requested in 1758 from Fray José de San Juan de la Cruz, a discalced Carmelite then living in Logroño, José Marzal y Gil de Tudela and the master of high school de Loyola, Fernando Agoiz. The plan chosen was that of the friar, with a chevet and arms of the Wayside Cross forming a trilobule covered by caps and a large dome over a drum in the space of the Wayside Cross. The walls and, especially, the roofs are covered with an order with plasterwork of fine rocailles in an atmosphere of contrasting illumination. Structures The ornamentation and light make this Wayside Cross a spectacular and colorful ensemble, which is enhanced by the golden altarpieces and the colors of the plasterwork on a white background. The material execution of the work ran to position of José del Castillo, stonemason of Piedramillera, Miguel and Juan José Albéniz, masons of Estella and Juan José Murga, sculptor of Oteiza, while the painted decoration was entrusted, in 1765, to the gilder of Los Arcos Santiago Zuazo, with conditioned of the mentioned Carmelite friar.

The set of plasterwork is of enormous effect, both on the dome and on the walls, with a great dominance of white backgrounds which, although characteristic of the rococo phase, may not have been so intense in the original project . The saints, evangelists and, above all, a cycle of the life of the patron, developed in the ring of the dome, with the most significant scenes of his legendary history, stand out. We will not describe any of this because it has been done on numerous occasions, but we will highlight one of the program that has disappeared today and whose existence has gone unnoticed. We refer to the paintings that decorated the walls of the chancel, to which Madrazo refers, taking the grade of the novena of the saint written, in 1877, by Luis Bermejo y Roncal and published on various occasions in Logroño (1880), Pamplona (1888) and Estella (1899). There we read: "The sides of the main chapel have figures painted in lifeand the same outside between chapel and chapel, simulating on one side a priest going out to celebrate mass and on the other, one dressed in a surplice". All this Madrazo judges as "toys" unworthy of the gravity and majesty of the sanctuary, although it was during the eighteenth century when architectural illusionism was imposed, which adds to reality figures and feigned architectures, making it more grandiose, imaginative and monumental. Ministers of the liturgy, entering or leaving through doors, had already been represented by Francisco del Plano in San Francisco de Viana, decades before. They constituted a usual procedure in this subject of illusionist paintings. It is very possible that those trompe l'oeil paintings can be found under the whitewashes.

The body of the main nave underwent a new intervention in the last decade of the 18th century, as a result of a project made by Diego Díaz del Valle (1796), documented by Víctor Pastor Abaigar, which would finally be carried out under the direction of the Riojan master Francisco Sabando, starting in 1797.

The true character of the interior of the nave are the paintings on its roof and, above all, the canvases painted by Ramón Garrido from Logroño in 1831, in which he depicted a cycle related to the life of the saint and his protection against plagues in the countryside. Madrazo was categorical about its artistic value when he affirmed a century and a half ago: "what a sad disappointment awaits those who, through the façade of this temple, of 17th century Italian taste, promise to find inside it statues and paintings of the famous machinisti of the same age! (...) Since they brought from outside who carved the beautiful statues of the exterior, why not have brought also, to paint its vaults and walls, frescoes like the Lanfrancos, the Marattas and the Cortonas?". Two of the canvases narrate the affliction of the people before the plague that devoured the fruits, cereals and vineyards in Navarre and La Rioja, asking for a remedy that came with the preaching of the saint and the repentance of the faithful. Curiously, the people represented in both cases wear 19th century costumes and clothing.