From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.
Example: Given Relationship: 'make', Sentence: 'Jenny made the announcement that her baby was an alien.'
Example solution: made
Example explanation: The output relationship - made, is a correct verb form of the given relationship - make, and it is also used in the given sentence

Problem: Given Relationship: 'be religion of', Sentence: 'We will see and experience the cultural richness of Turkey and how the spread of Christianity began , how Christianity became the religion of the state from an illegal sect in East Roman Empire .'
Solution: religion