Predjama Castle is one of the most astonishing sights in Slovenia and probably one of the most spectacular castles in Europe: a four-storey medieval fortress wedged into the mouth of a cave halfway up a 123-metre vertical cliff, as if it had grown out of the rock. It has clung to the precipice for more than 800 years, camouflaged against the grey stone, and even today it is hard to believe it is real when it appears at the end of the road. Guinness recognises it as the largest cave castle in the world.
Its strength was not only defensive: behind the castle lies a cave system with a stream running through it, and those secret tunnels are at the heart of its most famous legend. In the 15th century, the rebel knight Erasmus of Predjama (Erazem Predjamski), a kind of local Robin Hood at odds with the emperor, held out here through a long siege: while the imperial troops besieged him from the front, he secretly brought in supplies through the tunnels in the rock, and even —so the legend goes— threw fresh cherries at them from the walls to mock them. He was only defeated through betrayal.
This guide helps you plan your visit: how much admission costs (it is expensive, like almost everything in the Postojna park) and how to make the most of the combined ticket with the caves, what you can see inside its four cave-dwelling storeys, when you can tour the cave behind it, how to get there from Postojna or Ljubljana and why it is worth booking ahead. Predjama is the perfect complement to the Postojna Caves and one of those visits you never forget.
A fortification at the mouth of this Karst cave is documented as early as the 13th century, linked to the Patriarchate of Aquileia. The castle as we know it today, however, came later: after several rebuilds, it took on its current Renaissance appearance in the late 16th century, around 1570, under the Kobenzl (Cobenzl) family. Its most famous episode dates from the 15th century: the knight Erasmus of Predjama, lord of the castle and sworn enemy of Emperor Frederick III of Habsburg after killing one of the emperor's relatives, withstood a siege lasting months here (around 1483-1484) because the cave tunnels allowed him to bring in supplies in secret; according to tradition, he was finally betrayed by a bribed servant, who signalled with a light the moment Erasmus was in the most vulnerable part of the castle —the latrine—, where he was killed by a shot from a bombard. Afterwards the castle belonged to various noble families (Purgstall, Kobenzl, Cobenzl and, for almost three centuries, the Windischgrätz), until in the 20th century it passed into public hands and became a museum. The full story is on our history page.
Read the full history ↓Mediterranean Slovenia: the limestone plateau of the Kras, which gave the world's “karst” its scientific name, its colossal caves, the imperial stud farm of the Lipizzaner horses and a short stretch of Istrian coast with a Venetian feel, between Koper, Piran and Portorož.
Read the history of The Karst and the Adriatic coast →Some places make no sense on your own; with someone explaining them, they change completely. We look ours up on Civitatis: guided in Spanish and booked online with no fuss. They have 8 activities in Liubliana. And there are free tours here: you book without paying and tip the guide whatever you think at the end, so trying one costs you nothing. Have a look below: tap any of them to see them all.
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Origins, formation and what the sources say.
Before there was a castle, there was a cave. In the heart of the Slovenian Karst, water eroding the limestone opened a huge rock shelter in the side of a valley: a hollow at the foot of a 123-metre vertical cliff, which also led into a system of passages with a stream running through them. To the medieval mind, this natural feature was a defensive gift. The mountain itself protected it from above, its flanks could not be reached, it had water, and it offered a secret escape route deep into the rock. All it needed was a wall across the mouth to become an almost impregnable fortress.
That, in essence, was the first Predjama. The earliest records of a fortification here date back to the 13th century: around 1200-1274 there is documentary evidence of a castle linked to the powerful Patriarchate of Aquileia, the great ecclesiastical and feudal authority of the north-eastern Adriatic, which ruled much of what is now western Slovenia. The name itself, Predjama ('in front of the cave', pred jamo, in Slovenian, or Lueg in German), describes exactly what it was: a castle in front of, or inside, a cave.
That first fortress sat even deeper inside the rock shelter than today's castle, making the most of the natural protection. Over the following centuries it passed between various feudal lords of the Karst and Carniola, but its strategic value never changed. Whoever held Predjama held a place that could not be taken by storm, and in a world of constant feudal wars, that was worth its weight in gold.
Predjama's fame comes from one man and one siege in the second half of the 15th century. Erasmus of Predjama (Erazem Predjamski, Erasmus Lueger in German) was a local nobleman and lord of the castle who, at some point around 1480, made a mortal enemy of the imperial power. According to tradition, Erasmus killed Marschall Pappenheim, commander of the imperial army and a relative or close associate of Emperor Frederick III of Habsburg, in a duel to avenge a friend's honour. From then on, Erasmus was an outlaw and a declared enemy of the emperor.
Holed up in his castle hanging from the cliff, Erasmus did what rebel nobles of the time did. He waged his own war, raided the properties of the emperor and his allies, and behaved like a kind of knightly bandit, a Robin Hood of the Karst in the romantic version that came later. The emperor could not tolerate such defiance and ordered the governor of Trieste, Gašper Ravbar (Kaspar Raubar), to bring him to heel. So began, around 1483-1484, the siege that would make Predjama a legend.
The besiegers faced the same old problem this place always posed: the castle could not be taken by force. The mountain and the cliff protected it, there was no way to bring siege engines close, and it could not be starved into surrender... because Erasmus had an ace hidden in the rock.
The secret of Erasmus's resistance lay in the cave. Behind and above the castle, Predjama's network of karst passages ran through the mountain to an exit on the slope above, well out of the besiegers' reach. Through these secret tunnels, Erasmus and his men could slip out at night, gather food and supplies in the surrounding area, even launch raids, and get back in without the army camped in front of the castle noticing a thing. The siege dragged on for months (tradition says more than a year) and got nowhere: however tightly they closed the ring at the front, the castle would not surrender.
This puzzle gave rise to Predjama's most famous story. Legend has it that Erasmus, to mock his hungry besiegers and show them they would never starve him out, threw fresh food down to them from the walls: roast meat, bread and, above all, fresh cherries, which should have been impossible to get in a supposedly cut-off castle. Half provocation, half psychological warfare, the gesture became the symbol of Erasmus's cunning against the brute force of the Empire.
But every fortress has a weak spot, and Predjama's was, quite literally, its lowest and most exposed point. The only part of the castle that stuck out beyond the protection of the rock, within range of enemy fire, was the latrine, perched on a ledge. The besiegers knew it. All they needed was to find out when Erasmus would be there.
The siege was settled not by arms but by a bribe. Unable to take the castle, the besiegers bought off one of Erasmus's servants, someone who knew his master's routines. The deal was simple and grim: the traitor would signal with a light from a window the exact moment Erasmus was in the most vulnerable part of the castle, the latrine jutting out from the rock. One night the servant set the agreed light. The imperial gunners fired a bombard at that spot and killed Erasmus of Predjama with a single cannon shot, in the least dignified and least protected place in his fortress.
And so, around 1484, the rebel knight died, not defeated by an army but betrayed by one of his own. His death ended the siege and returned Predjama to imperial control. With its mix of heroism, cunning, humour and betrayal, the story had every ingredient it needed to become a legend, and it did: Erasmus entered Slovenian folklore as a romantic hero, an unruly nobleman who defied the emperor and could only be beaten by treachery.
It is hard to separate history from legend in the tale of Erasmus; contemporary sources are scarce and the myth grew over the centuries. But the setting is real and still standing. Anyone visiting Predjama today can see the latrine ledge, the mouth of the tunnels and the cliff from which, so tradition says, the cherries flew: the genuine backdrop to one of the best stories of medieval Slovenia.
The castle you visit today is not quite the one Erasmus lived in. That medieval fortress, set further back in the cave, was left damaged and outdated, and over the 16th century it was rebuilt and enlarged. Its current look (the elegant four-storey Renaissance façade fitted into the mouth of the rock shelter) dates essentially from around 1570, when the Kobenzl (Cobenzl) family rebuilt the castle and gave it the shape that made it famous. The use of the cave was kept, with rooms reaching into the rock and passages leading to the galleries, but with the comfort and taste of a Renaissance building.
Over the following centuries, Predjama passed through the hands of several noble families of Carniola. After the Kobenzls, and then other owners, the castle belonged for almost three centuries to the powerful Windischgrätz family, who kept it as one of their estates. Although it lost its military importance (with modern artillery, a castle hanging from a cliff was no longer impregnable), it kept its value as a unique residence and as a symbol, and it stood up reasonably well to the passage of time, protected by the very rock that shelters it.
In the 20th century, with the end of the great noble estates after the two world wars and the arrival of socialist Yugoslavia, Predjama passed into public hands. It was restored, turned into a museum and opened to visitors. Today it is run by the same company as the nearby Postojna caves, as part of the great tourist circuit of the Slovenian Karst.
21st-century Predjama is one of Slovenia's great tourist icons and an almost essential stop alongside the Postojna caves. Recognised by Guinness as the largest cave castle in the world, it draws crowds every year who come for the impossible sight of a fortress growing out of a cliff and for the story of Erasmus. You tour the inside with an audio guide (available in several languages, including Spanish) through its four cave-dwelling floors: the lord's rooms, the kitchen, the Gothic chapel, the dungeon, the armoury and the passages into the cave.
In the warmer months you can also visit Predjama Cave (Predjamska jama), the network of passages the rebel knight used to escape. It closes in winter to protect the bat colonies that hibernate there. And every summer, at the foot of the castle, the Erasmus Tournament (Erazmov viteški turnir) recreates the world of the 15th century with jousts, mounted knights, archers and a medieval market, bringing the legend back to life for a few days in its original setting.
From the 13th-century fortification tied to Aquileia to today's museum, by way of Erasmus's siege, the Kobenzls' Renaissance rebuild and the centuries of the Windischgrätz family, Predjama sums up eight hundred years of Slovenian Karst history at a single glance. Few places combine nature (the cave, the cliff, the underground stream) with history and legend quite like this one. It is no coincidence that documentaries and films have chosen it as a location: Predjama looks made up, but it has been real for eight centuries.
