These should not discourage further responses, but here is an earlier thread answering a similar question:
https://www.reddit.com/r/AskHistorians/comments/60wgyx/is_it_true_that_saint_patrick_driving_the_snakes/ by u/depanneur , u/alriclofgar

And further related discussion in a recent thread: https://www.reddit.com/r/AskHistorians/comments/84wi9l/was_the_christianisation_of_ireland_peaceful/ from u/alriclofgar and u/1MMRAM