A setting in the ancient past, when gods, demons, and monsters walked the earth. Often blends the mythologies of various cultures together, as the writers see the advantages for storytelling. Those writers are a crafty bunch. Also has the tendency to bring in plenty of anachronisms in terms of technology, culture, and so forth. The literary forerunner for this would be the Hyborian Age of Robert E. Howard's Conan stories, which mixed and matched milieus from different times and places: this way, Howard could have a series protagonist in a historical context, without worrying about historical inaccuracies.
Naturally, however, the concept of such an age is Older Than Dirt. Much myth and literature was written about a supposed time period in the distant past (i.e. before the Iron Age) that was chock full of ten-foot-tall warriors and interesting monsters to kill. Contrast Advanced Ancient Acropolis.
If we see the end of the age, that's End of an Age or The Magic Goes Away. May overlap Here There Were Dragons, Lost Technology, and Pointless Doomsday Device. See also Death of the Old Gods, which is when a setting's past is described this way. If the mythical beings were mostly evil, then it is The Dark Times.
In medieval Europe, the preceding dark ages were considered to be this, with historical rulers, dragons, dwarfs, sometimes gods figuring in countless heroic epics and romances. For the Ancient Greeks (starting from 800 BC to the Roman conquest in 146 BC) the Bronze Age Mycenaean Greek period from roughly 17501050 BC was seen as this as well, alongside the subsequent Greek Dark Ages, and provided the basis for Greek Mythology. Asian fiction subverts this trope somewhat, due to the prevalence of ancient records and artifacts. East Asian societies do have their own Time of Myths, such as the period of semi-divine emperors predating the dynastic period of China, but they were sufficiently well-discussed and codified before the advent of commercial fiction to never really crop up as a setting for genre fiction.
- Princess Mononoke. Bits of Japanese Mythology make appearances in other Ghibli films as well.
Narrator: In ancient times, the land lay covered in forests, where, from ages long past, dwelt the spirits of the gods. Back then, man and beast lived in harmony, but as time went by, most of the great forests were destroyed. Those that remained were guarded by gigantic beasts who owed their allegiances to the Great Forest Spirit, for those were the days of gods and of demons.
- Inuyasha the Movie: Fire on the Mystic Island has Horai Island, which was actually created in a legendary time, and was a place where humans and youkai lived peacefully, and many hanyou children was born.
- In the anime Claymore, the plot takes place in a world inhabited by man-eating demons called youma. An organization creates hybrids from humans and youma, because only they are strong enough to fight against the youma. But the hybrids are exclusively women. And each of the warrioresses runs the risk of losing control of their powers one day, and turning into a monstrous youma, an Awakened Being. The organization claims that they can not make male warriors.
- However, very long ago, in the first generation of the organization, most warriors were men. But almost all of the male warriors were quickly awakened, so the organization only made female warriors. And the time of the male warriors has so long since passed, that many warrioresses are surprised and confused when they have to fight against a male Awakened Being.
- The anime Magi: Labyrinth of Magic plays in an Arabic version of a mystical time when there were still monsters and magic.
- All incarnations of Sailor Moon have in their backstory the Silver Millenium, an era when the Solar System was ruled by a monarchy based on Earth's Moon. It falls when Earth rebels against it.
- In the comics of Hellboy it is shown that the Earth was once dominated by demons and monsters. Later it turns out that they still exist, and they want to dominate the Earth again.
- Movies by Ray Harryhausen: Clash of the Titans, Jason and the Argonauts, and the Sinbad trilogy.
- In Time Bandits, the bandits use a hole in space-time to travel to the Time of Legends, home to all sorts of mythical creatures, and wherein is imprisoned the Evil Genius. The implication in the story is that the Time of Legends is not a true historical time period, but rather a kind of pocket universe, only reachable by time-hole.
- The The Mummy Trilogy shows that the Bronze Age and antiquity were a world full of magic. Both the mummy Imhotep and the Chinese dragon emperor lived at this time before they became undead.
- The Cabin in the Woods shows that the world was dominated by cruel, ancient gods in the past. They hid themselves, and agreed to receive occasional human sacrifices. But toward the end of the film it is suggested that the old gods return.
- Larry Niven wrote a book series called The Magic Goes Away, which posits that magic and magical creatures, up to and including Gods were once real, but the Mana that powered them got used up, civilization fell into ruins, the Gods and monsters all died, and Man was left to huddle in caves for millennia until new ways of life could be invented.
- The setting of the Everworld book series, although in the modern day, is an alternate universe where all the mythological creatures and deities ran away to.
- The Age Of Legends in The Wheel of Time, basically a Utopia fueled by Magitek. It didn't end well. And the previous First Age is implied to be our own modern age.
- In Sword of Truth the war 3000 years ago between the Old World and the New. The Keep, the Confessors, the Chimes, Chainfire, the Palace of the Prophets, the Bond with Lord Rahl, innumerable books of magic, constructed spells, the Journey Books, the Towers of Perdition, and even the antagonist and the protagonist are all remnants of that war, brought back as the last smidgeon of that war.
- The age of The Gunslingers in The Dark Tower and of the Great Old Ones before them. Basically same as the above.
- Michael Moorcock's Corum books all open with a 'Time of Myths' introduction, which starts something like "In those days there were oceans of light and cities in the skies and wild flying beasts of bronze..." and goes on to recount this semi-mythical history for a while before an eventual segue into the story to date.
- The Elric Saga, also by Moorcock is implied to be Earth millions of years in the past. It's said that after the world ending war of gods, giant lizards would eventually develop then eventually a new society of humans with less magic.
- In The Hitchhiker's Guide to the Galaxy, the planet-building megafactory of Magrathea was built during a golden age:
"In those days spirits were brave, the stakes were high, men were real men, women were real women, and small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri."
- Tolkien's Legendarium: Tolkien's Middle-Earth is also one of these — part of the fiction is Professor Tolkien claiming the The Lord of the Rings and its related works were translations of long-lost volumes, thus setting the action in a forgotten age of our own world. The Elder Days in The Silmarillion, especially the Great Tales descended from The Book of Lost Tales, which reads exactly what it sounds like.
- A Song of Ice and Fire has the Dawn Age, when the First Men came to Westeros and made war on the Children of the Forest until the coming of the Others in the Long Night which almost destroyed the world. Then came the Age of Heroes, the time of many legendary figures of the setting, which lasted until the coming the Andals. Almost all of the noble families of Westeros claim descent from one of the many heroes that lived at this period.
- Dark Reflections Trilogy mentions that before the suboceanic kingdoms, and even ancient Egypt, there was a time when gods walked the Earth in their original forms. Then humans decided they prefer mute, stone statues to living deities and hunted them down. The Flowing Queen is actually one of these old gods, Sahment. There are hints Baba Yaga may be one herself, too.
- The Legend of Sigmar novels by Graham McNeill are the grimier, grittier version of this in the same vein as the Conan stories.
- The Kharkanas Trilogy is set millennia before the events of the Malazan Book of the Fallen and features characters and events considered mythical by the time of the main series. Here the Elder Gods are not even gods yet, and the Imass still mortal and K'rul has just made his bargain with the Eleint (dragons).
- The Stormlight Archive: For thousands of years, humanity fought beside the divine Heralds to force the Voidbringers off Roshar. The Heralds gave humanity the Knights Radiant, magical knights with Shardblades and Shardplate, along with stranger supernatural powers. After a hundred Desolations, the Heralds told humanity they had finally won, and left to fight the Voidbringers in the Tranquiline Halls. The story takes place four and a half thousand years after the Heralds left; Shardblades and Shardplate are priceless treasures, while the Knights Radiant have fallen and their powers forgotten. The time of the Desolations are called the Shadowdays, or more formally the Heraldic Epochs. People speak of them in hushed whispers, elevating the Heralds to near-godhood and trying to discover the secrets of the ancient Magitek. What they are unaware of is that he Heralds actually lied; they were so tired of fighting, dying and being tortured for centuries before being resurrected, that they couldn't take it any more. Now the Voidbringers are returning, but there is no one prepared to fight them.
- Mistborn: At the end of the original trilogy, one character takes up the powers of both Ruin and Preservation, becoming Harmony. That individual uses these powers to reshape the world into a near-paradise. Several hundred years later, in Wax and Wayne, this event is known as "the Final Ascension" or more formally "the Great Catacendre" ("the End of Ash"). The world before is known as "the World of Ash," or "anteverdant" (literally "before green"). The characters are often bewildered by the events that they are being swept up in, saying that kandra and gods are things of myths, not real life. Interestingly, the people actually have extremely detailed accounts of what the world was like before the Catacendre; Harmony kept meticulous notes, and left them behind. It's the sheer scale of events that makes people feel that they are more distinct than they really are.
- In The Mortal Instruments it is stated that the earth was regularly visited by demons for a long time until about a thousand years before the plot, the first Shadowhunters were created. Before that, humanity was at the mercy of demons, fairies, and evil warlocks.
- Later, it is also clear that at the beginning of this time, angels and demons together have children, and this was the first fairies. Perhaps some warlocks and fairies from this time are still alive even in modern times, since fairies are very long-lived and warlocks are immortal.
- In Percy Jackson and the Olympians and The Heroes of Olympus it becomes clear that the gods, heroes and monsters from the Greek and Roman myths actually lived, and many of them are still alive. Magic has not left the world, it is simply no longer perceived by modern people.
- The Dragonslaying Maiden is set in Scandinavia sometime before the start of The Viking Age, when the monsters of Norse Mythology roamed the land, settlements were few and far between, and dragons and armies of trolls could randomly raid your hometown. Since the narrator is Odin reflecting on the events surrounding the title character and he hasn't had much to do in the world for a millennium, he looks back fondly on the time period.
- The Witcher also has a time when humans first discovered the new continent, which was still dominated by many monsters.
- Conan the Barbarian, of course, codified the idea of such a setting. As stated above, Robert E. Howard created the Hyborian Age because he loved historical fiction, but didn't have the time or the resources to research a new historical period for every single story. Hence the Time of Myths, allowing him to drop Conan into a pirate adventure or a Viking battle with frost giants as he wished.
- The opening lines in Joseph and His Brothers by Thomas Mann go: "Very deep is the well of the past. Shall we not call it bottomless? ... The deeper we sound, the further down into the lower world of the past we probe and press, the more do we find that the earliest foundations of humanity, its history and culture, reveal themselves unfathomable." Mann postulates that figures in the Book of Genesis existed much further back in time than supposed, and the generations in the narrative are "coulisses," stage sets that screen the depth of field behind them.
- The Khokarsa series by Philip José Farmer are set in a Time of Myths that serves as a prequel to both Tarzan and She, describing an ancient matriarchal empire whose remnants would become La's Opar and Ayesha's Kor.
- In a land of myth, and a time of magic, the destiny of a great kingdom rests on the shoulders of a young boy. His name...Merlin.
- In Buffy the Vampire Slayer there was the Primordium Age, an epoch in which demons had dominated the earth for many millions of years. But The Powers that be changed this by exiling the demons into other worlds, so that humans could live on the earth. The last demons who had to go created the first vampires.
- Kröd Mändoon and the Flaming Sword of Fire: The series' ostensible setting, as Atlantis is once mentioned as having been destroyed in the past and some of the characters are "pagans" (albeit based upon popular cliches rather than actual ones).
- The Horslips' two concept albums, Book of Invasions and The Tain, are about the Heroic Age of the earliest Irish myths, where men, Gods and non-human creatures fought for the mastery of Ireland.
- Deep Purple's LP The Book of Taliesyn opens with a track revisiting early British/Celtic mythology via the bard/mystic Taliesyn. A lost Celtic kingdom called Taliesin existed in what is now the North of England/Scottish borders. Its last remnants fell with the Norman invasion in 1066.
- The first edition of Exalted ran with the idea that Creation was this to either the real world or the World of Darkness, with Creation undergoing successive revolutions and collapses that eventually left it diminished and bound into the world we know. The idea was eventually formally abandoned, but influences remain.
- Houses of the Blooded presents itself as about the Ven people out of the world's mythic past. Specifically, it's about playing in the style of the Ven's own popular dramas about their own history, which they heavily mythologized. Yes, the sourcebook is rich with Direct Line to the Author.
- Forgotten Realms has the Arcane Age, the Netherese empire of high magic and floating cities. Interestingly, Netheril was built on the lost knowledge of two previous civilizations in its own right.
- In Fate/stay night, older heroes and artifacts are more powerful than younger ones (compare, say Caliburn to Sigurd's Gramnote , then Gram would win everytime), particularly things from the "Age of Gods" before the rise of Christianity came. Age of Gods were full of True Ether (the kind of "air" that Gods breathe, and was the main source of magic) as well as having more "Mystery" (i.e the more Shrouded in Myth someone is, the stronger he/she potentially is) than the current time. This is displayed best perhaps when Caster fought Rin using spells requiring a single word to cast, while the latter (a genius albeit inexperienced magus in her own right) was forced to use gems that had months or years worth of stored prana to counter them. Although Rin admitted she would have been able to counter a few spells for each gem if she were more confident, it doesn't change the fact that a few words from a Magus of the age of gods is worth years of prana storage from a modern one. Additionally, Caster can manifest spells in a single word that require modern magi to chant for a full minute (or half a minute in the case of experts) to replicate, and one of hers contain several times the total prana of the protagonist.
- In the broader Fate Series, gods used to roam the Earth as the dominant species. But (as told in Fate/Extella), in around 12000 BC, an extraterrestrial being called "Sefar" came to Earth, then killed some of those gods and caused major devastation until it's taken down by the wielder of "the holy sword that projects the light of the Earth" (highly implied to be Excalibur). It marks the first decline of the "Age of Gods". Other points where Age of Gods is said to decline is when Gilgamesh rebelled against the gods and when King Solomon, the "King of Magic" died, with the age's end (and the start of "Age of Man") being the rise and spread of Christianity (0 AD).
- The most obvious video game example is named Age of Mythology, featuring Egyptians, Greeks, and Vikings fighting each other, and later the suspiciously Roman Atlanteans.
- The first few hundred years of a game in Dwarf Fortress are typically this, a time where mythical beasts and gods (the latter actually demons posing as gods) roam the land, civilization is usually in the bronze age and still expanding, and the world in general is a far more dangerous place. Fast forward some years (or kill the beasties yourself) however, and time passes into the ages of Legends and Heroes, moving ahead as more of these creatures are killed. Eventually, if all mythical creatures are killed and humanity ends up being the only surviving civilized race, the world passes into the Age of Civilization entirely. There's also an "Age of Fairy Tales" if the mythical creatures are almost wiped out except for the odd almost-literal Hidden Elf Village somewhere the other races can't get at it.
- A theme in Dominions; The Early age is an age where magic is commonplace. Mages are stronger, the various races are quite superhuman, and civilization hasn't progressed as far. Fast forward a bit, and the various civilizations have very developed metallurgy and are closer to a 1500s level of technology... and magic has dwindled. The non-human races have interbred with humans, and mages have become weaker.
- The time before the Early age is this to an even larger extent, where the creation stories of nations occurred and the gods and spirits were more actively involved in the world,
- In Ultima II, this was where Minax the Big Bad was living. Ultima II is the strangest of the games to explain canon-wise, because for some reason it takes place on Earth, yet later games say it happened in Another Dimension Britannia.
- The Elder Scrolls
- The series has the Dawn Era. In addition to the usual god walkabouts and wars, time was also nonlinear, as it hadn't been conceived of as a thing yet. A lot of strange stuff went down, and when it was over, most of the "original spirits" had become the Aedra, Daedra, and Ehlnofey that we know of today.
- In the series' primary Creation Myth, there were the "12 worlds of creation". Padomay shattered them because Nir (Creation) favored Anu. Anu put the pieces of these worlds together to create one world: Nirn. From what little is known about them, they were nothing like Nirn is today. The Hist are believed to come form one of these worlds. As are the Dreugh, who ruled one of them in the name of Molag Bal.
- Ōkami, combines Japanese mythology and folklore in cel-shaded ink-illustration.
- Titan Quest is an entire Action RPG about the Greek and Egyptian Time of Myths, with a trip into High Fantasy Wuxia later.
- Final Fantasy XII and, to a much lesser extent Final Fantasy Tactics are this to Vagrant Story, with magic going away more and more over the course of millennia.
- The God of War series, an ultra-violent take on the ancient Greek mythos.
- Asura's Wrath seems to take place in this at first, but many of these elements are actually mixed with Science Fiction and actually takes place in the far future, but the elements for this trope are extremely prominent.
- In Mass Effect 3, the Distant Finale reveals the legend of "The Shepard" has long since passed into the realm of myth. The entire series itself is implied to be the Stargazer recounting the story to his young grandson.
- Bravely Default has two of these, although they are only mentioned in the descriptions of items: the Age of Myths, which appears to be based on Greek Mythology, and the land of Wa, which vanished several centuries before the events of the game and is based on Japanese Mythology.
- RWBY: "The Lost Fable" reveals that before Remnant was... well, Remnant, it was a world where, as Jinn puts it, "Kings and their kingdoms were plentiful, and magic was a gift from the gods that everyone could wield." Basically, an full blown High Fantasy world, in comparison to the show's more Heroic Science Fantasy setting. That ended when Salem tried to lead a rebellion against the gods of light and darkness. This convinced them that humanity was a "failed experiment" and things just kind of went downhill for everyone after that.
- Disney's Hercules, which is (very, very) loosely based on the Greek myth of Herakles. To a lesser extent, Disney's Aladdin as well.
- In The Legend of Korra it is shown that humans lived in cities on huge lion-turtles because the wilderness was too dangerous for them. In the wilderness many spirits lived, and some of them were also evil and dangerous. At this time, the first Avatar was created, Avatar Wan. He sealed the spirits in the spirit world so that humans could leave the lion-turtles and inhabit the earth.
- In the course of the plot Avatar Korra opens the entrance into the spirit world again, because she has the hope that humans and spirits can live peacefully together.