1854: No Irish Need Apply - The New York Times
https://www.nytimes.com/2015/09/08/insider/1854-no-irish-need-apply.html
Before reading this article, I thought "No Irish Need Apply" was possibly a myth, but to the degree that it did occur it was pure bigotry. But the clippings shown are for Protestants wanting their children to be raised by Protestants; that's much more understandable.