The parochial church was built after the old Santa María de Balda Parrish was moved in 1510. It is a clear example of the Basque Gothic style, and its interior houses panels painted by the Schools of Madrid and Seville, as well as sculptures influenced by Antxieta and Neoclassical and Rococo style sets. It took on its monumental aspect in the 18th century. The tower, the portal, the vestibule, the vestry and the parochial house are from this time, all in the purest Baroque style, directly influenced by the proximity of the Loyola Sanctuary.
Its Romantic-Symphonic organ is known around the world. It was the last organ created by the Parisian Organ Workshop of Aristide Cavaillé-Coll in 1898.
Saint Francis panel
At the parish, visitors can admire the panel showing the philosophy of Jesuit Pope Francis I: the Saint Francis panel belongs to the Olano-Idiakez family. Dedicated to Saint Francis of Assisi, its iconography is completed with the Jesuit saints Saint Francis of Borja, Saint Ignatius of Loyola and Saint Francis Xavier.
Side Altarpiece of San Juan Bautista.
Polyptych of the Seville school, attributed to Peter de Villegas and Juan Bautista Vázquez the Elder, built by the Juan Pérez de Recalce family in the second half of the 16th century. It was reworked in the 18th and 20th centuries.
on the first level, San Lorenzo, the image of San Juan Bautista and San Marcos. On the second level, San Pedro, Adoration of the Shepherds and San Antonio. On the third level, San Martín offering his cloak, coronation of the virgin and Santa Catalina. The top level is crowned by the Calvary.
Main Altarpiece of Nuestra Señora de la Asunción
Designed by Francisco Bautista and built by Antonio Alloitiz, creator among others of the old altarpiece of the basilica de Nuestra Señora de Begoña in Bilbao. After a fire destroyed part of the building in 1905, it was restored under the direction of Francisco Urkola, architect of the Victoria Eugenia Theatre in San Sebastian.
twelve apostles, San Juan Bautista, San José, Santa Ana, San Joaquín, 4 Doctors of the church and The Virgin in her Assumption. Both sides of the Tabernacle contain two 16th century half bust reliquaries of the Virgins of Cologne.