Grand Catholic church known for its 12th-century mosaics & lavish interior with 22 Roman columns. The Basilica of Santa Maria in Trastevere; English: Our Lady in Trastevere is a titular minor basilica in the Trastevere district of Rome, and one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140–43.