Usage of the word heathen in the last five centuries peaked dramatically several separate times: in the 1520s, 1590s, 1600s, 1640s, 1750s, and 1840s. Perhaps that's when people were feeling particularly religious. Today, the word refers to any individual(s) outside of the scope of a major religion, but when it was encompassed by the Middle English word hethen, it referred specifically to people who weren't Christians or Jews. Same goes for the Old English word haethen, which was merged with Old Norse heithinn, meaning "pagan", to create the precursor to today's term. Both of those derive from Proto-Germanic haithi, a word meaning "uncultivated soil" (because pagans were "religiously uncultivated"; this is also the etymon of English heathland, "shrublike infertile land"), from Proto-Indo-European skayt, or "clear"
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd