 The first Jesuits appeared in the diocese of Tortona in 1566, after negotiations which had lasted nearly two years.The original cathedral was said to have been founded on the citadel of Tortona in the second half of the 4th century by Bishop Innocentius.It was dedicated to S. Sixtus and S. Lawrence, though the name of Sixtus was subsequently omitted, and that of Innocentius added.