How did it happen?
A clue is in this passage from Acts. After his resurrection, Jesus appeared to the disciples he had chosen to be his apostles. He told them that they were going to be empowered by the Holy Spirit to be witnesses to the ends of the earth."
They were. And they did.
from Psalm 47:
Sing praises to God, sing praises;
sing praises to our King, sing praises.