Cathédrale Saint-Jean-Baptiste de Lyon is a Roman Catholic cathedral dedicated to Saint John the Baptist, in Lyon, France. It is the seat of the Archbishop of Lyon. It was founded by Saint Pothinus and Saint Irenaeus, the first two bishops of Lyon. It is located in the heart of the old town (Vieux Lyon). Begun in the twelfth century on the ruins of a 6th-century church, it was completed in 1476. The cathedral also has the Lyon Astronomical Clock from the 14th century.