20th May 325: First Council of Nicaea brings together bishops from across the early Christian world

Several hundred bishops came from regions including Asia Minor, the eastern Mediterranean, and parts of the Latin West where they formulated the Nicene Creed, which affirmed that the Son was “of the same substance” as the Father.

27th October 312: Constantine the Great receives his Vision of the Cross, marking the start of his conversion to Christianity

While preparing for the decisive Battle of the Milvian Bridge, Constantine reportedly witnessed a Christian cross which may have been accompanied by a Latin inscription which roughly translates as ‘In this sign, you will conquer.’