Construction began in 1944, initiated by Bishop Leynaud, who recognized that the Cathedral of Saint Philippe -- the converted Ketchaoua Mosque -- could not serve permanently as a cathedral in a city where such conversions carried deep historical wounds. The Ketchaoua Mosque had been seized from Muslim worshippers at bayonet-point in 1831 and consecrated as a Catholic cathedral in 1832. Its transformation remained a source of resentment throughout the colonial period. Leynaud's new cathedral would be purpose-built and located away from the Casbah, in the modern part of the city. Designers Paul Herbe and Jean Le Couteur, working with engineer Rene Sarger, created a structure that broke sharply with traditional church architecture.

The cathedral's design reflects the mid-century modernist movement that was reshaping sacred architecture across the Catholic world. The building uses reinforced concrete in bold, sweeping forms that owe more to Le Corbusier's contemporaneous chapel at Ronchamp than to the Gothic or Romanesque traditions of French cathedrals. Yet inside, it holds traces of a far longer history. The altar is carved from Carrara marble and houses relics of African saints. At the entrance to the nave, small organs donated by the parish of Boufarik face a mosaic mural that dates to 324 CE, recovered from the first Roman basilica at Castellum Tingitanum -- modern-day Chlef. This single artifact bridges seventeen centuries: a Roman-era Christian mosaic incorporated into a modernist French cathedral on Algerian soil.

The cathedral was elevated to its current status in December 1962 and consecrated in 1963 -- the very year after Algeria won its independence. With the departure of nearly a million Pied-Noirs, the Catholic population of Algiers shrank from hundreds of thousands to a few thousand. The Ketchaoua Mosque was restored to Islamic worship, fulfilling what many Algerians saw as an act of historical justice. The Sacred Heart Cathedral became the seat of a drastically diminished archdiocese, serving a community of foreign workers, diplomats, and a small number of Algerian Christians. It remains a place of quiet worship in a city shaped by the collision of empires, faiths, and the long aftermath of decolonization. The cathedral endures as both a functioning church and a monument to the complexity of Algeria's layered religious heritage -- a building that exists because one faith's house of worship was taken to serve another, and then taken back.