Context: The predominant religion is southern Europe is Christianity. Christianity spread throughout Southern Europe during the Roman Empire, and Christianity was adopted as the official religion of the Roman Empire in the year 380 AD. Due to the historical break of the Christian Church into the western half based in Rome and the eastern half based in Constantinople, different branches of Christianity are prodominent in different parts of Europe. Christians in the western half of Southern Europe — e.g., Portugal, Spain, Italy — are generally Roman Catholic. Christians in the eastern half of Southern Europe — e.g., Greece, Macedonia — are generally Greek Orthodox.

Question: What is the main faith practiced in southern Europe?
Answer: Christianity

Question: When did the Romans make Christianity their official religion?
Answer: 380 AD

Question: What denomination of Christianity is common in the western part of southern Europe?
Answer: Roman Catholic

Question: Which denomination of Christianity is more common in the eastern part of Mediterranean Europe?
Answer: Greek Orthodox

Question: What is the main faith practiced in western Europe?
Answer: Unanswerable

Question: When did the Romans say that Christianity was true? 
Answer: Unanswerable

Question: What denomination of Christianity was common in Constantinople?
Answer: Unanswerable

Question: Which denomination of Christianity was most common during the Roman Empire?
Answer: Unanswerable

Question: Why are different branches of Christianity spread evenly over Europe?
Answer: Unanswerable