Classicly

"The Lost Valley of Iskander" is an El Borak short story by Robert E. Howard. It was not published within Howard's lifetime, the first publication was in the FAX Collector's Editions hardback The Lost Valley of Iskander in 1974. Its original title was "Swords of the Hills".  Terrific tale with Howard's great hero El Borak discovering a lost group of ancient Greeks. He helps them to fight off a horde of bad guys.