Thanks. It was Darby whose name I was struggling to remember. I think he lived in England in the 1800s when he interpreted certain Bible passages to define the rapture.
Depending on which version of the story you wish to believe, John Nelson Darby either plagiarized or invented the pre-trib rapture theory that is the mainstay of most independent/fundamentalist/non-confessional churches. One version of history has the notion coming from the ecstatic utterances of a young Scottish girl, Margaret McDonald. And as the story goes, Darby picked up and capitalized on the idea in his founding of the Plymouth Brethren.
In either case, the theory did not exist in Christian theology until the 1830s when it took root in one part of England.