The site it occupies was once the Roman forum of Trajan, the forum vetus, thus its name. It was built with private funds between 1872 and 1896 in a dominating position in the city, as a mark of the triumph of Christian values over the socialists of the Lyon commune of 1870, like the similarly-inspired Basilique du Sacré-Cœur, Paris. Its design, by Pierre Bossan, draws from both Romanesque and Byzantine architecture, two non-Gothic models that were unusual choices at the time.