Therefore? 

I had a quick question... I'm not a religious scholar, but something caught my eye... in the intro to this article it talks about God's embodiment in Jesus, and says "Christians, therefore, commonly refer to Jesus as Christ or Messiah."  I was always under the impression that he's called "Christ" because that was his name "Jesus Christ."  Is that not correct?  I know he's sometimes called "Jesus of Nazareth."  Was Jesus of Nazareth his official name?  Did we kind of appoint Christ as his last name?  If I'm wrong, that's cool, but it'd still be nice to know the truth P