Prehistory is full of creatures that could pass for fantastic; mammoths, sabre-toothed cats, dinosaurs and millions of others. The problem is, you might think of prehistoric human society as boring. The solution? Medieval Prehistory. Medieval prehistory involves vaguely prehistoric plant and animal life, or climate and environmental conditions, with knights, castles, and princesses coexisting. Doesn't necessarily have to be set in Medieval Europe or a Fantasy Counterpart Culture to it, but it does have to involve a pre-industrial society. So Ancient Grome and Ancient Africa or even Mayincatec etc. are permitted. Stone Punk, which usually involves a more modern-type society, is an entirely different trope. Subtrope of Anachronism Stew (though usually technically does not fit under that heading due to being set in a secondary universe) and often Alternate History or Historical Fantasy, usually based on the premise that the asteroid did not wipe out the dinosaurs or that somehow other wildlife managed to survive up until the medieval era or something involving Time Travel. Don't expect the wildlife to live in the areas they did in reality. Related to Dinosaurs Are Dragons and often overlaps with Fantasy Kitchen Sink. Not to be confused with One Million B.C., which involves stereotypical stone-age 'cavemen' living alongside creatures such as dinosaurs, or Prehistoria, its video game equivalent. Can contain elements of The Dark Times and The Time of Myths, or Ambiguous Time Period, and Domesticated Dinosaurs.
- Marvel 1602 has dinosaurs in Elizabethan America. Explained by Neil Gaiman (though not in story) as being because the Savage Land is bigger in this version of the Marvel Universe.
- 10,000 BC, has a pyramid-building culture using mammoths as beasts of burden.
- The B-movie Aztec Rex has the Conquistadors battling a Tyrannosaurus rex in a Mayincatec setting.
- The Conan the Barbarian franchise counts as an example, being set in a prehistoric alter-earth.
- A few times in The Elenium, the villains use time portals to make enemies from the prehistoric past attack the protagonists. These include a Tyrannosaurus rex and a hoard of "dawn men" (the common ancestor of humans and trolls in this 'verse).
- The Garrett, P.I. novels, gumshoe-style mysteries set in a fantasy-world city, count both dinosaurs (thunder lizards) and assorted Pleistocene mammals among their Verse's typical fauna.
- A small element of The Lord of the Rings uses this. The Drśedain west of Gondor differ greatly from the normal humans, and even from the nonhuman races, and it has been suggested that they are actually Neanderthals. Though not explicitly so, creatures like the Mūmakil and Wargs could be seen as exaggerations of mastodons and dire wolves respectively, while the nazgūl's flying mount may be some kind of pterosaur. Justified as according to Word of God it is set in the Time of Myths in the distant past of earth.
- Similarly Lyonesse and its sequel Green Pearl take place in a pre-Migration Period world with fantasy elements and a vaguely medieval culture.
- The Reynard Cycle: Aurochs, a pre-historic breed of cattle, are used for labor in Calvaria.
- A Song of Ice and Fire
- The series has mammoths, direwolves and dwarf elephants. A number of more elusive creatures have also been theorised to be based on prehistoric creatures also e.g. that the 'unicorns' of Skagos were really the extinct elasmotherium, or that the 'giants' are really an extinct species of ape, the Gigantopithecus.
- The "terrible walking lizards" brought from Sothoryos to be sold to Braavosi menageries sound a lot like Deinonychus or Utahraptor.
- The irregular 'winters' could also represent shorter versions of glacial periods rather than actual seasons, although Word of God indicates that they actually have something to do with magic.
- Dungeons & Dragons has stats for dinosaurs, dire wolves (among other "dire" beasts), mastodons, and megalodons. Plus several others. Though whether or not they're actually part of the setting depends on the campaign.
- This dates back to Gary Gygax's original Greyhawk campaign from the 1970s (which was heavily altered prior to its commercial release in 1980). Since he didn't have time to run gaming sessions on an almost nightly basis and create a detailed fantasy world, he set his adventures in an alternate version of North America. The Great Lakes region was a civilized area (the cities of Greyhawk and Dyvers were expys of Chicago and Milwaukee, respectively), while the western part of the continent was considered a "land that time forgot" full of cavemen, dinosaurs, and other prehistoric creatures.
- The Eberron setting has the Talenta Plains, where nomadic tribes of halflings travel on the backs of dinosaurs.
- The Hollow World facet of the Mystara D&D setting is home to several classical- or Dark Ages-era civilizations, existing alongside vast tracts of dinosaur-populated wilderness.
- The bestiary in GURPS Banestorm includes "bushwolves", "paladins", and "treetippers" - from their descriptions and illustrations, they're evidently thylacines, glyptodonts, and giant ground sloths by other names. "Striders" may be one of the many species of flightless predatory bird that appear from time to time in the fossil record.
- The Elder Scrolls V: Skyrim has sabre-toothed cats, cave bears and mammoths, as well as vaguely medieval humans.
- World of Warcraft is a Fantasy Kitchen Sink setting with many medieval and Tolkienesque elements. Many creatures resemble or are directly based on prehistoric animals: there are raptors, sabretooth cats, woolly rhinos and mammoths; the kodo beast resembles a brontothere and the plainstrider look like a terror bird. Also, there is Un'Goro crater, a Lost World filled with pterosaurs, stegosaurs and Devilsaurs (which are, essentially, Tyrannosaurus rex).
- Age of Conan has mammoths and woolly rhinos along with civilized humans. It takes place in the Hyborian Age.
- The Empire of Blood in The Order of the Stick has civilized humans and dinosaurs coexisting.
- Some Christian creationists believe that medieval stories of dragons and suchlike creatures are actually accounts of dinosaurs, who, so the hypothesis goes, coexisted with man, survived Noah's Flood, and died at the lack of oxygen in the antediluvian world.