The Old Catholics established their church to challenge papal authoritarianism, particularly the doctrine of papal infallibility.
The Old Catholics: A Protest Against Papal Infallibility
Angelic Hierarchy in the 6th Century: Developing Church Theology
The theology of the angelic hierarchy developed in the sixth century and was the result of Jewish and Neoplatonic influences on Christianity.
How the Christian View of the Afterlife Developed
The Christian understanding of the afterlife did not spring fully grown from Jesus, but evolved in the early years of the church by Christian reflection.
Reincarnation and Christianity: How a Theological Concept Was Lost
Jesus talked of everlasting damnation, but he gave no systematic account of what happens to those who die before the Age to Come arrives. Many early Christians believed in some form of reincarnation, but that the idea fell out of favour in the sixth century.
The Filioque Problem – A Thousand Years of Schism
In 1054 papal legate Cardinal Humbert marched into the Orthodox Cathedral of Hagia Sophia in Constantinople and banged a bull of excommunication onto the altar. The Greek emperor tried to reconcile the two sides to no avail. The split between the churches dates from then.