The answer is more complicated than you might think. Even at the beginnings of Greek literature, Olympus was not, or not just, an impressively cloud-capped mountain in Thessaly. In the Iliad, Olympos is both an actual peak (with epithets like “snowy” and “craggy”) and a metonym for the heavens. At times, Homer’s Olympus is clearly conceived as something more than a physical mountain, as when Zeus tells the other gods:
“If you tied a chain of gold to the sky, and all of you, gods and goddesses, took hold, you could not drag Zeus the High Counselor to earth with all your efforts. But if I determined to pull with a will, I could haul up land and sea, then loop the chain round a peak of Olympus, and leave them dangling in space. By that much am I greater than gods and men.” (Iliad 8.19-26)
This dual conception of Olympus as both physical peak and heavenly realm continues throughout Greek (and later Latin) literature. The discrepancies between these conceptions are clear in the mythological compendium known as Apollodorus’ Bibliotheca (probably written in the second century CE). In a myth about twin giants who attempted to storm the homes of the gods, the author notes:
“When they were nine years old and measured eighteen feet across by fifty four feet tall, they decided to fight the gods. So they set Mount Ossa on top of Mount Olympus, and then placed Mount Pelion on top of Ossa, threatening by means of these mountains to climb up to the sky” (1.53)
Here, at least, there is a clear distinction between Olympus and the home of the gods. The distinction in even clearer in Lucian’s Icaromennipus, a satirical second-century text about a man who decides to fly to the home of the gods. Mennipus (the protagonist) doesn’t bother with Olympus; he sets sail directly into the sky, and figures that the gods live very far off indeed. To quote his calculations:
“Let me see, now. First stage, Earth to Moon, 350 miles. Second stage, up to the Sun, 500 leagues. Then the third, to the actual Heaven and Zeus’s citadel, might be put at a day’s journey for an eagle in light marching order…”
By the time Lucian wrote, the educated elite, at least, tended to think that the gods were everywhere (the Stoic idea), nowhere (the Epicurean idea), or scattered among the stars (the Platonic idea). Calling the home of the gods “Olympus” had by then become little more than a convention.
So – having determined that many Greeks (at least in the post-classical era) probably didn’t believe that the gods actually lived on Olympus – did anybody climb the mountain?
We don’t know whether any Ancient Greek ascended to the highest summit of Olympus. We do know, however, that hundreds of Greeks routinely climbed to the sub-peak now called Hagios Antonios, about a mile away from (and only 300 feet lower than) the summit. There, from the third century BCE to the fifth century CE, offerings were made at an altar of Zeus.
From Hagios Antonios, there is a clear view of the craggy summit. It would have been obvious to all those who sacrificed at Zeus’ altar that there were no gilded palaces or sunbathing gods on top. There seems, however, to have been a lingering sense that Olympus was a special place. According to Solinus, writing in the third century CE:
“The things that are to be seen at Olympus show that Homer did not celebrate it rashly. First, it rises so high, with a preeminent peak, that the inhabitants call the top of it heaven. On the summit is an altar dedicated to Zeus. If burned offerings of entrails are brought to it, they are neither blown off by windy breath nor washed away by rain, but as the year rolls on, whatever is left there is discovered unchanged; what is consecrated to the god triumphs over time and the corruption of the air. Letters written in the ashes remain until the next year’s ceremony.”
In the post-classical Greek imagination, the gods may not have lived on Olympus. But nor were they far away.