In the Old Testament, which was the part of the Bible written before the birth of Jesus, it predicted that a King will come who will bring salvation to the world. It called this King a Messiah which means someone who is anointed (meaning someone who God has poured his oil upon), meaning someone who is chosen by God. When God chose King David, he had his prophet Samuel go and pour oil on his head. That was the symbol that God has chosen him. The word Christ and the word Messiah is the same word, just in different languages. They mean the same. So, Christ is not Jesus’ last name. It’s his title: The Messiah, the Promised King, The Anointed One, the Chosen One.