The Mosque–Cathedral of Córdoba stands on a site where Roman and late antique buildings preceded the Islamic monument. A longstanding tradition describes a Visigothic church of Saint Vincent shared and then purchased by Muslims, though modern scholars debate the evidence for that precise sequence. What is certain is that Abd al-Rahman I, survivor of the overthrown Syrian Umayyad dynasty and founder of an independent emirate in al-Andalus, began a monumental congregational mosque in 785–86. Its alternating stone-and-brick arches created a distinctive forest of columns.

Successive rulers enlarged the mosque as Córdoba’s population and political importance grew. Abd al-Rahman II extended the prayer hall in the ninth century. Abd al-Rahman III, who proclaimed a caliphate in 929, expanded the courtyard and built a new minaret. Under al-Hakam II in the tenth century, craftsmen created the richly mosaicked mihrab, domed bays, and royal enclosure. Al-Mansur added a vast eastern extension around the end of the century, producing the irregular plan visible today. The building expressed Umayyad legitimacy, scholarship, wealth, and Córdoba’s status as a leading Mediterranean capital.

Castilian forces under Ferdinand III captured Córdoba in 1236. The mosque was consecrated as a Catholic cathedral dedicated to the Virgin, and Christian worship began without demolishing the whole prayer hall. Chapels, tombs, altars, and liturgical furnishings accumulated among the columns. The former minaret became a bell tower. This reuse preserved an extraordinary portion of the Islamic structure, but it also asserted conquest and transformed the building’s religious meaning. Muslim communal worship did not continue there.

The most dramatic Christian intervention came in the sixteenth century, when a Renaissance nave, transept, and choir were inserted into the center. Construction began with royal approval despite local controversy and continued across generations. Gothic, Renaissance, Baroque, and later elements joined the Umayyad fabric. Nineteenth- and twentieth-century restorers uncovered Islamic features, removed selected later additions, and sometimes pursued an idealized image of the mosque. Such work shaped modern perceptions as decisively as medieval conversion had done.

The monument was declared a Spanish national monument in 1882 and entered the UNESCO World Heritage List in 1984; the designation expanded to Córdoba’s historic center in 1994. It remains an active Catholic cathedral and major visitor site. Debates over ownership, naming, interpretation, and Muslim prayer show that its history is not politically settled. The building cannot be reduced to either harmonious coexistence or simple erasure. It preserves material evidence of Umayyad rule, Christian conquest, liturgical adaptation, artistic rivalry, modern restoration, and continuing disputes over how Spain represents its Islamic and Christian pasts.

Recent conservation must manage both the extraordinary columned hall and the many Christian chapels embedded within it. High visitor numbers, humidity, structural movement, fire risk, and the needs of worship require constant negotiation. No restoration can return the complex to a single original state without destroying another historic phase. Its integrity lies precisely in the visible and sometimes uncomfortable accumulation of religious, political, and architectural decisions made over more than twelve centuries of contested urban and devotional life.