How did Christianity spread in the early years after the death of Jesus?

A.
Early Christians revolted against Roman rule and established their own empire.

B.
The pope ordered Christian soldiers to spread Christianity during the Crusades.

C.
Jesus's followers traveled to different cities and spread his sermons and teachings.

D.
Emperor Augustus converted to Christianity and made it the official religion of Rome.

C. Jesus's followers traveled to different cities and spread his sermons and teachings.