what happened to them?

Forty days after His resurrection, Jesus left this earth and ascended into heaven. That is where he is right now, seated at the right hand of God always making intercession (praying) for us.

He told His disciples to wait in Jerusalem for the power (Holy Spirit) to come and then they were to go out into all of the world and spread the good news (gospel) about Jesus.

Acts 2: 1-4 "And when the day of Pentecost had come they were all together in one place. And suddenly there came from heaven a noise like a violent, rushing wind, and it filled the whole house where they were sitting. And there appeared to them tongues as of fire distributing themselves, and they rested on each one of them. And they were all filled with the Holy Spirit."

After this the disciples were no longer timid and afraid and powerless. The coming of the Holy Spirit changed everything for them and for us. They understood the gospel and they were empowered to go and do what Jesus had commissioned them to do.

We know they were successful because we know the gospel that they took out into the world.

Ever wonder what happened to them?

John died of extreme old age in Ephesus.
Peter was crucified, head downward, during the persecutions by Nero.
Andrew died on a cross at Patras, in Acchia, a Greek colony.
James, the elder son of Zebede, was beheaded in Jerusalem.
Thomas, the doubter, was run through with a lance at Coromandel, in the East Indies.
Phillip was hanged against a pillar at Neropolic, a city of Phrygia in Asia Minor.
Matthew was slain by the sword in Ethiopia (Abyssinia).
Thaddeus was shot to death with arrows.
Simon died on a cross in Persia (now Iran).
Judus Iscariot, after betraying the Lord, hanged himself. (author not named)

Obviously the disciples obeyed.