Ireland was one of the few areas of land NOT conquered by the Roman's because ov its harsh climate and rough people. This allowed Irelands pagean religion to thrive much longer than other western European cultures. Because of this, Ireland had a people who were very reluctant to conversion. It took a long time to rid the area of there gods and goddesses and charms. Even when Ireland was finally converted, the irish still clung deeply to certain parts of there pagean culture. This is evident in there art and symbology through hundreds of years. But as for st. Patrick chasing the snakes away, this was real, in a way. I have heard and read that it wasnt snakes that were "driven out" it was the disease rattled rats that were making people sick. St Patrick was a smart man and he decided to introduce snakes to the towns to kill the rats. His plan was successful and when the rats were gone he had one last task, to rid the island of snakes and thus Ireland was saved. Hope that helps, happy early pattys day everyone.