Horseclans is a science fiction series by American writer Robert Adams, set in a North America that had been thrown back to a medieval level by a full-scale nuclear war.
The books mainly concern the doings of the "Horseclans", a nomadic people originating from the "Sea of Grass"—the Great Plains from present-day southern Canada to central Texas, and from the Mississippi River to the Rocky Mountains.
The Horseclansmen are portrayed as fierce, noble and often gifted with telepathy, which came in handy for their dealings with their horses and "cats"—sabertoothed tigers that had been revived by scientific means in the years before the nuclear war.
The main Ehleen kingdom, Kenooryos Ehlas (New Greece), was dominated by a thoroughly corrupt, debased version of the Greek Orthodox Church, and the conduct of whose rulers was, in some ways, also reminiscent of Hellenistic kings.
In a similar fashion to the world of Robert E. Howard's Conan and of Jack London novels, civilization is seen as having a softening and corrupting influence in comparison to the hardy Ahrmenee and the Horseclans, although not to the extent that they outweigh the peace and prosperity that Milo and others work towards.