Did Omis or its Landscape Give Rise to the Pirates?

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The Omis landscape was ideal for the rise of the Omis pirates because it provided a unique configuration of river, mountains, hidden canyon and a town from which to operate. The river provided access to the Adriatic, the mountains restricted movement making Omis defensible, the hidden canyon provided secluded anchorage, and the town ensured physical support.

Omis

The Croatian road trip which started in Rovinj is now pointing south towards Omis on the drive from Split to Dubrovnik. This route, the Poljicka Cesta, proceeds along the scenic Dalmatian coast. The passive, blue Adriatic to the right contrasts with the rugged mountains of the greyish uplifted landscape on the left.

Omis, at first sighting, appears to be a small, historical old town which is like so many other limestone and dolomite towns along the Croatian coast. The old town of Omis is bordered by three natural features of the landscape, these being the Adriatic, the Cetina river and the mountains. The Cetina provides access in one direction to the Adriatic, and access in the other direction through the mountains to the interior. Omis is sheltered and protected because the mountains ensure restricted movement through the landscape. But the squeezing of Omis between the sea and the mountains, although providing for a picturesque setting, can obscure some important questions. Did Omis simply locate in this extraordinary landscape, or did the landscape create the town? Which raises other questions. Why is Omis located at the mouth of a river, squeezed on a narrow coastal margin without potential for expansion? What is the role of this landscape in the development of piracy in Omis? The answers to these questions are not found in a stroll around the old town. The answers are found in the geology that produced this remarkable location and the geography that provided the opportunity for its use.

The Source and Stability of the Omis Landscape

The dramatic Omis coastline and interior canyon is dominated by the steep Poljica and Omiš Dinara mountains which at Omis are separated by the Cetina canyon. These mountains resulted from uplift along the Dalmatian coastline which was caused by the continental collision between the Eurasian Plate and the Adriatic microplate. The collision compressed and folded the thick sequences of marine carbonates. These are now seen at Omis and along the Dalmatian coast as rugged mountains and eroded limestone cliffs. Deep synclines also formed which were drowned by the Adriatic. These define the Dalmatian islands that are so enjoyed by tourists and holiday makers. The cliffs, mountains and canyons that surround Omis are evidence of the magnitude of the forces involved.

Geologists have identified an overturned anticline in Omiš Dinara. You may recall from you school geography lessons that an anticline is an arch-like fold structure with the oldest beds at its interior. The overturned syncline at Omis has a limestone core. It is the result of the compression tectonics of the Cretaceous and Miocene epochs which was referred to earlier. Structurally it is a component of a large sheet of rock which is the source of the slopes above the city of Omis.

This is not all good news for Omis. As attractive as it is, the geology includes steep, overturned limestone cliffs and steep reverse faults. The result is unstable rock blocks prone to frequent rockfalls. Omis is located at the base of the steep limestone slopes and threatened by rockfall, leading to the installation of rockfall barriers.

The Cetina and its Canyons at Omis as Part of the Croatian Karst

Karst topography occurs across Croatia and neighbouring countries, and we have written about Karst topography in previous posts. Examples include;

• The Drive From Plitvice To Split And A Window On Croatia
• Lovcen National Park With Panoramic Mausoleum And Karst Landscape
• The Village and Hike At Lukomir In The Highlands Of Bosnia

So would it be unusual for the Cetina to be a karst river? We can compare the Cetina with the Korana River that streams through Plitvice and Rastoke. In fact, the whole Cetina catchment is karst terrain dominated by limestone and dolomite. The source of the Cetina River is a karst spring located in the foothills of the Dinara mountain range in Croatia. Underground drainage systems brought the water from this and other springs to the Cetina River. It is also worth a stopover if in the area of the Cetina Spring. The Cetina has travelled about 105kms from its source to its mouth at Omis, and is comparable with the Korana in that it flows by both surface and subterranean channels.

The Omiš canyon was formed by the Cetina River cutting through the surrounding coastal Paleogene limestone mountains. At the coast, however, the geology around the river mouth includes Eocene flysch deposits, while river sediments have accumulated around the estuary. The canyon extends 8 kilometres upstream from Omis. It is a protected landscape and has experienced geological erosion rather than glaciation. The cutting of the canyon floor may be ongoing because it is very possible that the tectonic uplift is still occurring.

The canyon is a classic example of karst geology which has already been explained in our posts about Plitvice and Rastoke. Here you are seeing another expression of the same processes where chemical erosion have been significant over time. It is worth noting that the canyon is also in a geological zone of clastic material in the form of transported and deposited rocks such as sandstone, shale and conglomerate. The presence of clastic rocks may have influenced the eventual cutting and shaping of the canyon.

The Significance of the Omis Landscape to the Omis Pirates

So why have we explained the Omis landscape is such detail? When we arrived at Omis we saw a landscape comprising a coastal margin of land which was divided by a river and a background mountain range. But we started to understand the very real geographical advantages those natural features provided. Those simple observations we made on our arrival at Omis were really of a protected waterway, a route inland, a connection to the Adriatic, steep terrain, restricted approaches, and elevation which could be used for observation.

The landscape explains much of Omis’ history. The same landscape that constrained settlement was now offering significant advantages. The landscape comprised a natural and protected harbour, a route through a hidden canyon to the sea, elevation for observation, and space for a town to support habitation. The pirates could see that Omis was defensible and that is why the pirates operated from there. It was the landscape that was the strength behind the pirates, not the town.

The Natural Harbour of Omis

The natural harbour of Omis, with channel surrounded by mountains, was unusually favorable for any who wished to exploit its geography. The key to the piracy was access to the sea and restricted visibility when the the ships were at anchorage. The natural landscape of Omis provided both.

The narrow coastal margin of Omis is bounded by vertical limestone and dolomite mountains, evidence of the uplift of the Dinarides. The Cetina river had for millennia eroded the rock face which had prevented its progress to the sea. This action and associated tectonics meant a gap eventually formed to facilitate the Cetina’s continued flow across the coastal margin into the Adriatic. This extension of the Cetina provided access for the Omis pirates.

The landscape behind the mountainous boundary is quite different but may have been equally important for piracy. The pirates could sail the short distance into the enclosed waters of the deep Cetina canyon located behind the mountains. The channel winds itself through the canyon’s steep terrain and may have provided both out of sight anchorage and a route to avoid vessels that chased them. The landscape’s natural harbour and secluded cove minimised visibility from the sea and maximised defence.

The landscape of Omis provided both secure anchorage and the conditions for the Omis pirates to maintain their vessels. They used light crafts that were not only fast and mobile in the open sea, but also remarkably manoeuvrable in the waterways behind the town. Heavier vessels may have followed the pirates into Omis but would not have been able to apprehend them in the shallower waters of the canyon.
Seven hundred years have now passed since the exploits of the Omis pirates, yet for all the history that has passed, Omis is still remembered as the ‘pirate town’.

The Period of Omis Piracy

Who Were The Narentine Pirates of the Mediaeval

The period of Omis’ piracy was preceded by that of the Narentines, a South Slavic tribe which settled near the Neretva River. The Neretva River flows as a delta into the Adriatic just south of Neum, the partial Bosnian enclave within Croatia that provides Bosnia with access to the Adriatic. The Narentines, between the 7th-10th Centuries, raided the Venetian trading ships and even forced this larger empire to pay tribute to ensure the safety of the merchants. A detailed description of the Narentine piracy and their eventual defeat by Venice can be read at Narentines

The Emergence of the Omis Pirates

The decline of the Narentines did little to remove the fundamentals of trade along the Adriatic or the reliance of small maritime communities to access produce. Nor did it rearrange the coastline which for so many centuries had aided the Narentines to plunder the trade routes. Much to the chagrin of the Republic of Venice, the decline of the Narentines only saw the subsequent emergence of the pirates from Omis. The Omis pirates not only attacked the merchant ships from the Republic of Venice, Dubrovnik, Kotor and Split, but also the ships carrying resources to the lands of the Crusades. The Omis pirates prevailed. Dubrovnik and Kotor both made treaties with them, and Venice again had to pay tribute to ensure free sailing and trade.

Significant maritime tensions existed during this period of the Mediaeval, primarily between Venice and Hungary, although the Byzantines, Genoa and Dubrovnik were also involved. The conflicts imposed necessity on smaller coastal communities to defend against potential threats and to support their economies. Consequently, piracy was tolerated by these communities along the coast as being economically beneficial.

The year 1420 brought change to the Adriatic. It was the year when the Republic of Venice, with a navy that eventually massed to three thousand ships, assumed domination of the Adriatic.The Venetian rulership is well documented by the influence of Venetian architecture along the Adriatic coastline. It would continue for a further 400 years. Omis’ period of piracy in the Adriatic, which had lasted for more then three centuries, eventually ended when Venice assumed maritime power. They resisted for a further 24 years before the end of their piracy.

The following are some of the posts that describe destinations that were influenced by the Venerians..

• A Croatia Road Trip Starting At Rovinj To Must See Destinations
• Piran Charms As A Gothic Attraction
• Trogir: What to See In This Captivating Medieval Old Town
• Make Your Visit To Budva Even More Interesting

What Evidence is There that the Landscape Enhanced Piracy at Omis?

The Mirabela Fortress

The Mirabela Fortress (also called Peovica) was built in the 13th century and is located directly above the old town. But why put a fortress here? It tells us much about how Omis functioned. The pirates of Omis used the fort for two major purposes. These were observation and communication. Firstly, warnings could be raised if unwelcome vessels approached the Omis coast. Secondly, readied pirate ships in the gorge or channel could be alerted to merchant ships in the vicinity.
Mirabela is quite accessible for visitors to Omis by a manageable and short climb up the mountain side behind the old town. The climb is rewarded by panoramic views across the old town, the river, the sea and the longer Omis coastline.

Starigrad Fortress (Fortica)

Whereas the Mirabela fortress was important to local communication, the Starigrad fortress (Fortica) was situated much higher above Omis at about 262 meters above sea.
The visitor can see from Starigrad the panorama of the landscape we have been discussing. Here the geography and its advantages to the pirates becomes visible. All at once. the relationship between sea, coastal margin, town, river, canyon and mountains becomes readily apparent and the dependence of the pirates on the landscape become clear.

Starigrad Fortress is the larger fortress and a hike to Starigrad takes about an hour of sensible walking. The fort was built in the 15th century during the Croatian-Ottoman conflicts and provided a refuge and final defensive stronghold against Ottoman invasions. Starigrad is far from its original condition but remains of the watchtower, thick defensive walls and bastion is evidence of how it proved to be a formidable defensive asset to Omis.

Omis Old Town

Omis, like so many other coastal Croatian cities, has an old quarter that is a maze of limestone alleys and lanes that separate mediaeval buildings constructed from limestone masonry. In the days of the Omis pirates the old town was physically squeezed between the mountains and the sea on the southern bank of the Cetina. For that reason, Omis is still quite small compared to other limestone towns.

The old town has its share of attractions and churches like St Peter’s (Romanesque 10th Century) are worth visiting. However, in view of the topic of this post, we have chosen to detour around an extensive coverage of the buildings and architecture of Omis old town and instead refer visitors to our site to descriptions of larger old towns along the Adriatic coast which bear the same styles.

• A Croatia Road Trip Starting At Rovinj To Must See Destinations
• Piran Charms As A Gothic Attraction
• Spot The Kotor Architecture Of Churches, Palaces and Buildings

Nevertheless, It is well worth a stroll through the Old Town as an evidence of prior piracy.

For the Recreational Visitor to Omis

There are many activities to enjoy in Omis, but interestingly, all bear a relationship with the foregoing discussion. That is because they are different ways of sampling the landscape that shaped Omis and its piracy.
Visitors can walk the old town which brings them into contact with the river and the harbour, and experience its compactness. Visitors can enjoy the markets and shopping. They can climb to the forts or follow the river using boats, kayak or raft. And, of course, they can experience the sea and swim along the coastline. One of the more pleasant pastimes is to drive a little way outside Omis and photograph the canyon along the Cetina.

Conclusion to Did Omis or its Landscape Give Rise to the Pirates?

Omis offers something different to what you are likely to see during your visit to Croatia. The piracy history is interesting as is the use of the secluded harbour and limestone cliffs which provided undiscovered anchorage. The location of Omis on the edge of the uplift provides plenty of opportunity to seek out its structure and evidence of the forces that were involved.
The limestone attractions continue just an hour away. Check out the following post :

The Imotski Sinkholes And The Drive From Omis

So the answer to Did Omis or its Landscape Give Rise to the Pirates? The landscape.

Q&A

What is the depth of the water in the Omis canyon?
The Spring source of the Cetina (also known as Milaševo vrelo) has a measured depth of approximately 130 meters, though some reports claim depths that are deeper.
The fact that visitors enjoy water sports like rafting in the lower reaches of the Cetina suggests shallower levels. The depth probably varies along the canyon although it can be navigated by lighter craft.

How high are the cliffs of the Omis canyon?
The canyon walls can be estimated on site at about 100–300 meters above the river.

How far from the gap in the mountains is the sea at Omis?
1–2 km

What is the drive to Omis like from Split?
The drive from Split is very pretty. The road passes through a number of coastal towns framed by the sea to one side and the rising mountains to the left.

How far is Omis from Split and how long does the drive take?
About 25lm and 40 minutes at a relaxed pace

How big is Omis?
Omis has a population of 15,000 persons

References

https://www.geotech.hr/en/geotechnical-investigation-works-port-of-omis

Marin Sečanj, University of Zagreb; Snježana Mihalić Arbanas, University of Zagreb Faculty of Mining Geology and Petroleum Engineering; Martin Krkac, University of Zagreb Faculty of Mining Geology and Petroleum Engineering; Sanja Bernat Gazibara, University of Zagreb Faculty of Mining Geology and Petroleum Engineering April 2019
Preliminary rockfall susceptibility assessment of the rock slopes above the Town of Omiš (Croatia)
Conference: ISRM Specialised Conference GEOTECHNICAL CHALLENGES IN KARSTAt: Omiš, Croatia

Duplančić Leder, T., Leder, N. and Baučić, M. (2020)
Application of Satellite Imagery and Water Indices to the Hydrography of the Cetina River Basin (Middle Adriatic)
Transactions on Maritime Science. Split, Croatia, 9(2), pp. 374–384. doi: 10.7225/toms.v09.n02.020.