Where did Christianity spread to by 600 ce?

West: Empire of Franks, kingdoms of Burgundy, Lombardy, Visigoths, Britain and Ireland. Not yet among the Saxons, Alamanni, or Norsemen.

East: Roman (Byzantine) Empire, Sassanid Empire (where it completed with Manichaeism), most of the Arabian Penninsula and the Axumite Empire.