I recently read Hilliard Belloc’s the great heresies, and he says that Islam is actually a Christian heresy. This makes sense considering that Islam recognizes Jesus as a prophet and venerate the Virgin Mary, but declares that Jesus was not divine. It is basically an extension of the Arian heresy but formed into a brand new religion.
Go read Chesterton's The Flying Inn...
It is basically an extension of the Arian heresy but formed into a brand new religion.
Islam is way beyond the Arian heresy. On a simplistic level I understand but many of the Arian persuasion would today be considered arguably normal Christians. Islam rejects both the Old and New Covenants and is replacement nonsense. From a textual critical view scripture wise not even comparable to the the Bible much of it incomprehensibly written in mostly 3rd person at a 6th grade grammer level.
There were a lot of religious influences back and forth.
Islam influenced the Eastern Roman empire in the 8th century in the form of iconoclasm — the destruction of religious images and icons. The warrior Isaurian emperors adopted iconoclasm.
Iconoclasm in turn alienated the Vatican, which had heretofore recognized the suzerainty of the Eastern Roman empire, and this contributed to the division of eastern and western Christianity.
The primary Christian heresies in the Middle Ages were derived from Manichaeism, which predated Islam. The duality here was between the the material world and the spiritual world, and this was a reflection of a dualism between a unitary good God (the God of the spirit world) and an evil god of the material world.
This concept of God was closer to the Moslem Allah than to the Christian, and in fact the Bogomils of the Balkans (a Christian heresy) converted in large numbers to Islam following the Ottoman conquest.
Yes that makes sense - I remember reading that Mohammed talked to Arians quite a lot. IIRC, it's the Arians who say that Jesus was substituted at the time of crucifixion - this is a tenet of Islam, too.