Day of Pentecost, Birthday of the Church A.D. 33
Death of St. John at Ephesus 97
The Ten great Persecutions of Christians 64-313
I. General Council, at Nicea 325
II. General Council, at Constantinople 381
III. General Council, at Ephesus 431
IV. General Council, at Chalcedon 451
Leo the Great revised the Roman Liturgy 492
V. General Council, at Constantinople 553
Gregory the Great revised the Roman Liturgy 590