Since 1633 the Trinitarian monks preached in Alcázar de San Juan, an action that generated benefactors such as two relatives of the Inquisition: Juan Guerrero Portanova and Bernarda de Úbeda, who were the main promoters of the future Trinitarian convent and church. The foundation would take place despite the fierce opposition of the Franciscan monks who, since the construction of the convent of San Francisco, had captured all the prominence in the locality.
In 1647 Juan Guerrero and his wife signed the deeds for the construction of the convent in which the clauses imposed by the patrons were marked, ensuring their recognition as patrons by virtue of which their noble coat of arms appears on the walls of the temple and the convent.
The monastery functioned normally until the disentailment of Mendizábal in 1834 forced the thirty Discalced Trinitarians who lived in the convent to abandon the place. From that date on, the monks’ cells were inhabited by poor families. Thanks to this movement, the convent was preserved and was not destroyed as was the case with other convent buildings in the city, such as the convent of San Francisco or San José. The church also suffered the disentailment, and worship was not restored until 1844 and became part of the parish of Santa Quiteria in 1879.
It is a baroque church with three naves, the central one larger than the lateral ones. It has two doors, the lateral one, of smaller size, shows the coat of arms of the Trinitarian Order, with the red and blue cross inserted in a lobed structure, adorned by a crown and reliefs of vegetal character.
The main entrance is inserted in a curtain façade, or front-altarpiece, very used in the Spanish baroque, restored in 1750, built in the characteristic reddish stone so used in Alcázar de San Juan, which is located in the noblest sides as corners, plinths and covers, being the rest built in masonry. Decorative elements and ornamentation cover almost the entire facade. The main façade acts as a bell tower, giving it a triangular appearance and emphasizing its verticality, something that is highlighted by the two pilasters located on both sides of the entrance, pilasters of giant Tuscan order. On the left side there is a mechanical watch dial. The entrance is guarded by a semicircular arch supported by pilasters and decorated with cushioning. On the second level of the façade is located the date that marks the end of the construction of the building: 1725.
It originally had a bell tower. That construction, however, was lost in 1834 as it had been built on a slope. Today, the bells are located in a large belfry in the upper part of the façade, both from the Casa Mutua de Vitoria, brought to the town in 1954.
Inside, the three naves are connected to each other through the arcade that runs through the building. The lateral ones are connected to chapels, which communicate with each nave also through semicircular arches. The transept is covered by a dome supported by pendentives with large medallions depicting Saint Michael of the Saints, Saint Thomas of the Virgin, Saint John the Baptist of the Conception and Sister Marcela.
At the head of the church, above the crypt, is the main altar, where the altarpiece with an ambulatory that holds the image of Jesus the Nazarene stands out.
