Though Chaosium's Call of Cthulhu was first released in 1981, for some reason, it's this ad, from issue #71 of Dragon (March 1983), that I particularly associate with its early days:
August Derleth as it does to H.P. Lovecraft. You can see its powerful Derlethian influence in this advertisement, which paints Call of Cthulhu as a RPG about "brave men and women [who] stand between the world as we know it and the unutterable evil of the Old Ones." Coupled with the ad's title -- "Adventurama" -- there's an undeniable pulp vibe to the whole thing, more Indiana Jones than the cosmic nihilism that purists like to claim for the game. I've never had a problem with this myself; I doubt a "pure" Lovecraft game would be very palatable to most gamers, then or now.