Complex sentence: The pope Gregory XIII granted the local confraternity of the Santissimo Sacramento permission to build the church as a shrine to house a fragment of the True Cross brought to this town in the first half of the 18th century.
Split into simpler sentences: The pope Gregory XIII granted the local confraternity of the Santissimo Sacramento permission to build the church. Later the shrine gained a fragment of the True Cross brought to this town in the first half of the 18th century.