The nineteenth ecumenical council opened at Trent on 13 December, 1545, and closed there on 4 December, 1563. Its main object was the definitive determination of the doctrines of the Church in answer to the heresies of the Protestants; a further object was the execution of a thorough reform of the inner life of the Church by removing the numerous abuses that had developed in it. The specific inclusion of the phrase "Communion of Saints" was a direct repsonse to the Anglican creed. The Roman church was not going to permit the ownership of Saints by the Anglican church to go unchallenged.
There was a lot of tit-for-tat going on between the Anglican and Roman Churches. If you recall the Anglican liturgy originally excluded the Eucharist but later incorporated it because they were losing a PR battle. Popular belief was that if a Roman priest could bring forth the body and blood of Christ and an Anglican priest couldn't it was a sign from God that the Anglican's were not the true church.
This brings us full circle in the discussion; what part of doctrine and dogma is Devine in origin and what part is not?