Built on one of the mosques of the Islamic city, the oldest documentation of its construction dates from 1402 and 1417.
Church with a single nave, with chapels between buttresses, originally in Levantine Gothic style. The primitive Gothic work of the fourteenth and fifteenth centuries is currently much transformed by the reforms and additions made between the sixteenth and eighteenth centuries.
The Main Portal, must have been built around 1488, coinciding with the Cortes held by the Catholic Monarchs in Orihuela, is framed by two pinnacles and a frieze of blind arches, presents archivolts with columns and decoration of cardines, tympanum with the coat of arms and motto of the Catholic Monarchs and partelúz with the figure of Santiago Apóstol, work by Ãngel Ferrant from 1947-48 in replacement of the previous one destroyed.
Between 1560 and 1561 the entire nave was raised in height, raising it to the same height as the first section, next to the door, which had already been raised previously, semicircular arches and tercelet vaults were made, the works were carried out by Julián Alamiquez, Ferrando Véliz and Juan Ruiz.
The works of the Renaissance extension of the temple began in 1546, when the Main Chapel and the Sacristy were built. The Main Chapel was built between 1549 and 1609, its design is due to Jerónimo Quijano, Juan Inglés, Julián de Alamiquez, AgustÃn Bernardino and Antonio Torregrosa participate in the direction of the works. It was conceived as a unitary complex in which the transept, presbytery and sacristy are framed. Its central plan was created as an autonomous space with alternating large exedras and niches, covered by a large vault that is supported by four large crossed arches. The Main Chapel is separated from the rest of the temple by a triumphal arch structure, as a large doorway.
The Sacristy, probably a work by Jerónimo Quijano made around 1546. It has an octagonal floor plan covered with a dome partially decorated with coffers and topped with a lantern.
The Chapel of the Communion, a Baroque work built in the eighteenth century during the important renovations that took place in the temple. It is located at the foot of the temple, perpendicular to the nave. It was built between 1726 and 1735 by Alfonso Ortiz and Felipe Sánchez and enlarged by Antonio de Villanueva in 1757. It has a rectangular floor plan, on the roof there is a dome with a lantern, on pendentives. It has an interesting façade, the work of Antonio Perales, with the typical scheme of Baroque altarpieces, in two bodies with Solomonic columns, a marked play of curved lines and decoration of plant stylizations, caryatids and themes alluding to the Eucharist.
To the "treasury" of the parish belongs an interesting set of works, mainly by goldsmiths, currently not exhibited to the public, among which we can mention: a Gothic-style Chalice (around 1500); Processional Cross in gilded silver (1570-72).
In the nave, next to the entrance, there is an organ built in 1770 by MatÃas Salanova and remodelled in 1881 by José Rogel, with a Baroque case by Ignacio Castell (1744-1746).
In the presbytery tabernacle made between 1792 and 1796 with oil painting of "El Salvador" by JoaquÃn Campos (1776) and sculptures of "The Four Evangelists" and "Santiago Apóstol" (1796) by José Puchol Rubio, also by this author is the "Apostolate" of the Main altar, with images made between 1773 and 1774 in carved wood and stuccoed in white, like those of the tabernacle; the choir stalls were designed by Antonio Villanueva in 1757.
In the chapel of San José, a Baroque altarpiece by Ignacio Castell and "Sagrada Familia", by Francisco Salzillo, works made between 1765 and 1766, San Vicente Ferrer and San Luis Beltrán, also by Salzillo, were added in 1775.
In the Chapel of San JoaquÃn with Saint Anne and the Virgin, a Baroque altarpiece from 1776-1777 with a sculptural group with the representation of the titular saints and young angels of Salzillo, from the altarpiece of the Sagrada Familia.
In the Chapel of Consuelo, crucified in polychrome wood by José Puchol Rubio made in 1795.
In the Chapel of the Communion the grille is the work of Antonio Gironés and Juan Escudero 1770; by Antonio Villanueva are four oval canvases located on the pendentives of the dome "San Gregorio", "San AgustÃn", "San Ambrosio" and "San Jerónimo", mid-eighteenth century; and the Baroque altarpiece in gilded wood dedicated to San Francisco de Paula made by Antonio Perales in 1733-1734.
In the Sacristy, the tiles, drawers and mirrors and the carving of "Crucified", a work by José Esteve Bonet from 1781, stand out.
Other works preserved in the parish of Santiago are "La Sagrada familia", a canvas by Pedro Núñez from Oriola, from 1767, and San JoaquÃn, Santa Ana y la Virgen Niña (1770-1780), by Antonio Villanueva.