For my breakfast reading at the moment, I am enjoying Pius IX And His Time by the Rev Aeneas MacDowell Dawson which I obtained free of charge from Amazon. It is fascinating to discover the scope of the ministry of Blessed Pio Nono and his concern for the Church throughout the world at a time when his own liberty and life was threatened.
In the midst of great troubles, he consulted the bishops of the world on the advisability of defining doctrine of the immaculate conception of our Blessed Lady. He gathered in Rome the largest concourse of Bishops since the 4th Lateran Council in 1215. The question arose whether the bishops would assist him in coming to a decision and pronounce simultaneously with him, or leave the final judgement to him alone. MacDowell reports:
[...] the debate, as if by inspiration from on high, came suddenly to a close. It was the Angelus hour. The prelates had scarcely resumed their places after the short prayer, and exchanged a few words, when they made a unanimous declaration in favor of the supremacy of St. Peter's chair: Petre, doce nos; confirma fratres tuos - "Peter, teach us; confirm thy brethren."