In his Jesus of Nazareth, M. Casey writes
Taking his ministry as a whole, it is evident that he saw himself as the kind of figure who was later to be hailed as ‘the Messiah’, though he did not use the term of himself, because it was not yet properly established. After his death and Resurrection, his followers did use the Aramaic meshīḥā of him. They needed titles for him, and meshīḥā was flexible enough for this purpose, because it was in use for a variety of real and expected figures. Moreover, he had played a fundamentalrole in salvation history, and he had believed that God had chosen him for that role. The church neither believed in nor expected any other anointed figure, so the title became unique. When Christianity spread to the Greek- speaking diaspora, the Aramaic meshīḥā was translated into Greek as ho Christos, because the Greek Christos was already used for similar terms in the LXX. At this stage Jesus was more uniquely anointed than ever, and Christian leaders continued to study the scriptures. This is why the term ‘Christ’ became so common.