Belief in this Jesus and his teachings have produced the largest religion in the world, Christianity. The name “Christianity” comes from Jesus because his followers believed him to be “the Christ” (“Messiah” in Hebrew), which means the "anointed one" of God foretold by Jewish prophets many centuries earlier. So “Christ” is not Jesus’ last name.
Time is literally counted from the believed birth of Jesus, so that the year 2018 would mean 2018 years after his birth. B.C. stands for "before Christ."
No matter what they believe about him, no reputable scholar denies that Jesus had a significant impact on world history.