Complex sentence: Father Francis de Sales Brunner, the missionary who led the "Precious Blood" order of priests, was a collector of relics, and he was responsible for the first collection of relics in Maria Stein.
Split into simpler sentences: Father Francis de Sales Brunner, the missionary who led the "Precious Blood" order of priests, was a collector of relics. He was responsible for the first collection of relics in Maria Stein.