Before San Lorenzo became the cathedral, San Siro was the principal church of Genoa — it held cathedral status until the 10th century and the Bishop of Genoa was based here. The current building dates largely from the 17th century, with a baroque interior of great richness and a magnificent early 18th-century organ that is still used for concerts.
The church is on Via Roma, one of the main streets of the 19th-century city, easily visited in passing. The organ concerts, when scheduled, are among the better musical events in Genoa outside the Carlo Felice season.