5000 years ago, huh? Sure, let's talk about the Minoans, especially since you already teed that one up by referencing u/rkoloeg's post.

Are you familiar with Greek myths? Theseus and the Minotaur? Strong factual basis (though no actual bestiality, as far as we know).

The Minoan civilization on Crete started at point we're not entirely clear on, but likely as early as 3500BC, with their more complex palace-based societies developing around 2000BC, slowly declining after approximately 1500BC, and going boom during the Bronze Age collapse, approximately 1200-1150BC. King Minos, his wife, the divinely given bull she fucked, and the Minotaur she gave birth to are all fictional, to the best of our historical and biological knowledge. What we do know is that the Minoan civilization loved them some bulls and bullfighting, as seen in their extant artwork(as you saw in rkoloeg's example). Frescoes like these were a common adornment in the Minoan palaces. These were massive and complicated structures that appear to be the center of day to day life in Minoan Crete, but that we don't currently have a strong idea of the purpose of, political, economic, religious, or some combination of the above. Given that many of the extant pieces of writing from the palaces look like they could possibly be inventory lists, it's often assumed they served some sort of economic purpose, possibly as centers of trade, and some of the artwork suggests religious purpose, but we really don't know anything for sure.

The reason we know so little about the Minoans is because of the little snag about their writing system. They had two, Cretan hieroglyphs and Linear A. We can't read them. At all. We have many accidentally preserved examples (the palace at Knossos burned, and burned buildings plus clay tablets equals long-lasting baked clay tablets), but no way to parse the language, which leaves a great deal of Minoan culture a complete mystery. Minoan Crete had a vast maritime trading empire stretching from Greece to Egypt and all points in-between, with Minoan artifacts and related paraphernalia, including more of their frescoes, found in an area stretching across the southern and eastern coasts of the Mediterranean from Egypt to Anatolia.

Society began to decline approximately around 1645BC (dated according to ice cap studies in the 1980s), because sometimes that island that looks like a crater that you live near (or in the case of one unfortunate Minoan colony, live on) is just an island that looks like a crater, and sometimes it's a 300 mile long volcanic caldera primed to go Yellowstone all over everything. The resulting tsunamis devastated coastal settlements while earthquakes brought down many of the palaces, though evidence suggests that most of the ash cloud luckily blew in a different direction. While earlier historians believed that the Minoan eruption (as it's often now referred to) wiped out the civilization, it's now understood that they held on for more than two centuries afterward, though obviously weakened from their height.

Then the Mycenaeans arrived. Either lusting after the riches of the vast trading empire, sick of being the victims of piracy, or for other reasons, starting in approximately 1420BC, people from mainland Mycenaean Greece were suddenly shacked up in the Minoan palaces, using the Minoan Linear A alphabet to write their own language, a combination we call Linear B (unlike A, we can actually read this), which spread from Crete back to mainland Greece, being the oldest Greek script we're able to parse, before it vanished during the Greek dark ages, approximately 1100-750BC. They mostly adapted Minoan customs to their own needs, and life tromped on. And then it didn't. By 1100BC, the majority of the population died, or left on their own, history doesn't record. Theories range from invasion from the mainland, the historical boogeymen known as the Sea Peoples, another volcanic eruption, or an outbreak of disease.