12.

 How did Pope Leo III demonstrate his rejection of the filioque?

            Pope Leo III wrote Charlemagne a letter stating that while he considered the filioque to be doctrinally sound, he did not consider it right to tamper with the wording of the Creed. The same pope had the Creed without the filioque inscribed on two silver plaques-one in Latin and one in Greek — and installed in St. Peter's.