The ongoing archaeological research in Oddi in South Iceland forms part of a multi-disciplinary project called The Oddi project (Oddarannsóknin), which consists of three major components of research: archaeological research dealing with the economic infrastructure of Oddi, environmental studies and studies in literature, and history focusing on Oddi as a central place. 

The project aims to shed light on the literary culture in Oddi, a regional power center in South Iceland during medieval times, focusing on the 1100-1300 period.

The 2018 excavation – manmade caves

In 2018, two test trenches were dug in an area called Hellirsdalir (lit."Cave Valleys"). The place name and the topography suggest collapsed manmade caves, which may be linked with the earliest written evidence for manmade caves in Iceland. 

Among the miracles of St Þorlákr, collected in 1199 to support his canonization, there is a story of a cattle cave in Oddi which collapsed and killed all the cattle inside, except for one cow, which was rescued thanks to an invocation to the saint. It has been suggested that the cave of this story is one of the collapsed caves in Hellirsdalir. 

The 2018 excavation confirmed that the long and deep depressions in Hellirsdalir are indeed collapsed manmade caves. In addition, a small, intact cave was discovered, which connects to the collapsed one. Based on tephrochronology, the small cave is thought to have been dug out in the 10th century and was already out of use sometime before the Hekla eruption in 1158.

Since 2020 this cave and a turf building in front of it have been excavated, as well as parts of the collapsed caves that connect to them. 

The standing cave was half filled with sand and blocks of collapse from the innermost part of the roof. Photo: Fornleifastofnun Íslands / Institute of Archaeology, Iceland

Mysterious artificial caves

A wide variety of methods have been used in Oddi, including field survey, excavation, coring, and geophysical survey. In addition to the cave site in Hellirsdalir, which is being excavated, the field survey has revealed a great number of artificial caves found within the home field of Oddi. Some were also found at a location near an ancient ruin within the estate, thought to have been a shieling. 

These caves have not been dated, but the fact that they seem to have collapsed or been sealed off for a long time indicates that they were out of use many centuries ago. There are no written sources mentioning artificial caves in use in Oddi in the last centuries. 

From the number, size, and distribution of these structures within the Oddi estate, they seem to have been very important and widely used as houses in the past.

Artificial or manmade caves are quite common in South Iceland, where around 200 known caves have been dug into the soft sandstone and tuff, which are characteristic types of rock in the area. Some of these caves have been in use up until the 20th century, and many of them are quite young, but for most of them, we have no secure knowledge of their age or duration of use. 

The discoveries already made in Oddi demonstrate that the number of artificial caves in South Iceland is much higher than previously thought since many of them have collapsed or gone out of use and were forgotten.

The excavation area. The church in Oddi is in the back. Photo: Fornleifastofnun Íslands / Institute of Archaeology, Iceland

The Viking Herald reached out to Kristborg Þórsdóttir, an archaeologist at the Institute of Archaeology in Iceland, to find out the latest project updates.

TVH: In your expert opinion, what are the most exciting aspects of the excavation/research?

KÞ: The research in Oddi is exciting in many respects. It has revealed the oldest dated example of a manmade cave in Iceland. It is also the first extensive excavation of this type of structure (in Iceland). 

The fact that the cave in Oddi seems to have been dug out in the 10th century AD makes it a Viking Age structure, adding to our previous knowledge of the building techniques of the first settlers in Iceland and of the people of the North Atlantic in that time period. 

TVH: How would you describe the importance of the manmade cave system that you're studying?

KÞ: The cave we have been excavating is, in fact, a Viking Age house that is still standing. It is a unique feeling to be inside a roofed building from that time period. Our research shows that the making and use of manmade caves in Iceland were widespread and started earlier than was previously known. 

From our experience in Oddi, many structures of this type have been sealed off and forgotten in the past and have yet to be rediscovered.

TVH: What is your current research focus within the cave system?

KÞ: We have been focusing on excavating what seems to be the only part that has not collapsed and a turf-built ruin in front of the cave. These structures served as outhouses for livestock and hey/winter fodder. This year we also started digging out a part of the collapsed cave system, which seems to have been ruined very early, but other parts that were still standing seem to have continued in use until they also collapsed.

TVH: What can you tell us about the area where the cave system was discovered and its cultural significance?

KÞ: Oddi is a large farm in South Iceland where some of the most powerful chieftains in Iceland used to live in the period 1100-1300 CE. They had enormous wealth and influence and were associated with the royal family in Norway. Sæmundur fróði (Sæmundur the learned) is one of the best-known members of the family (b.1056-d.1133). He was sent to central Europe to study there, and when he returned to Iceland, he became a prominent figure in the society and is believed to have written some of the earliest literary works in Iceland. 

Oddi became a center of power and influence but also a center for culture and learning. Snorri Sturluson, the famous writer, was fostered in Oddi by Jón Loftsson (Sæmundur's grandson). The wealth and influence of the chieftains in Oddi were based on a firm economic founding. The cave system being excavated is an example of Oddi's large-scale farming in the 10th century.  

TVH: What will your research in the area focus on in 2022? 

KÞ: We have already finished our field season for 2022. We do not have secure funding for further research. Still, we would like to finish excavating the cave that is still intact. However, that will be difficult due to safety reasons since the sandstone that the cave is dug into is deteriorating and crumbling. 

We would, of course, also want to continue digging out other parts of the collapsed caves to get a better understanding of how these buildings were made, what they were used for, and how they were modified during the time they were in use.  

A leg of a horse had been carefully placed within a turf wall at the mouth of the cave in later stages of its use. Photo: Fornleifastofnun Íslands / Institute of Archaeology, Iceland

Editor's note: The expert overview of the Oddi project was provided by archaeologist Kristborg Þórsdóttir at the Institute of Archaeology in Iceland.

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