How was Saint Francis of Assisi called by God?

In his early years Francis lived a very wild and sinful life. He decided at one time to become a knight and go to battle against a neighboring town. He was taken prisoner and thrown into jail. While a prisoner, God sent him a message that he needed to turn his life around and work to restore the Church. Once released from prison, he renounced his previous life and devoted the rest of his years to preaching and helping the poor.