Christianity is the catch-all phrase used to describe religions based on the beliefs that Jesus Christ is the son of God; that his life, crucifixion, resurrection and ascension to heaven are proof of God’s love for humanity and forgiveness of sins; and that by faith in Jesus people may attain salvation and eternal life. Christianity’s holy text is the Bible, especially the New Testament, but the Old Testament is also considered as sacred scripture.
Over its 2,000 year history, the church has been divided into three broad divisions: Roman Catholic, Eastern Orthodox and Protestant. There are further divisions within these three categories, with Protestantism claiming a particularly large number of different denominations.
So, it is correct to say that the main religion of Austria is Christianity, but it would be more specific to say that is mainly Catholic, since almost 75 percent of Austria’s residents are Catholics.