The big stick is the correct answer.
They started to plant tobacco which they got very famous and other cash crops
Answer: The Roman Empire converted them
Explanation: When the Roman Empire took over, they converted their religion, changing their Greek gods into Gods of the empire, then eventually Christianity became a mass religion and many polytheistic and pagan individuals were forced into Christianity.
The Greek gods are still believed in by some people, called "Hellenic Pagans". If you believe in the Greek gods still, I recommend checking it out.