Answer:
That would depend on the direction.
Saul was traveling to Damascus to further his persecutions of Christians, when he encountered a meeting with the risen Jesus Christ who asked him why he was persecuting Him. After some dialog, Paul was stricken with blindness for a number of days. Afterwords, his name was changed from Saul, to Paul.
(this is of course a condensed version, look into the New Testament for further inquiry).