Complex sentence: He was present at the synod which passed the canon recognising "the See Of the Apostle Peter" as the final court of appeal in difficult cases, this canon is to be found in the Book of Armagh.
Split into simpler sentences: He was present at the synod that passed the canon recognising "the See Of the Apostle Peter" as the final court of appeals in difficult cases. This canon is to be found in the Book of Armagh.