Nearly 20 years after Robert E. Howard's death: Conan had fallen out of public consciousness, but still had a cult following -- L. Sprague de Camp, a longtime fan, looked to capitalize on this by writing his own Conan pastiches (as well as rewriting many of Howard's non-Conan stories to star him). He would also team up with fellow writer Lin Carter to be his partner.
While their stories were popular at the time, and along with the help of Frank Frazetta they managed to bring Conan back into mainstream popularity, over the decades they have come to be seen in a more negative light, with some accusing them of exploiting/plagiarizing the work and memory of Howard.
Still, they managed to write a number of successful Conan stories, starting in the mid-1950s all the way up to 1980.