Let's make it clearer for the morons. By 400 AD the state religion of the Roman Empire (the one led by Constantinople) was the one now called Orthodox Christian. Most people in the Empire converted to the Christian religion, including those living in Palestine. Now shut up morons.
But not the Jews that lived in the area who stayed as Jews. Up to the mid 7C the Jews were not molested by the romans or Christians. Come the muslims and everyone in Palestine was forced into converting to islam or being killed. This resulted in the genocides and ethnic cleansings of Jews and Christians for 100 years until the muslims were the majority