The wrecks of two medieval merchant vessels known as cogs, unearthed during excavations in Varberg, Halland County, on the west coast of Sweden last year, have now been securely dated to the mid-14th century.
The results from these first analyses have also shed light on where and how they were constructed.
Cogs were single-masted vessels commonly used for trade across late medieval northern Europe.
‘These wrecks are a very special discovery, both in Sweden and abroad, so it has been fantastic to find them,’ said excavation leader Elisabet Schager of Arkeologerna. ‘Before these two wrecks were discovered, only seven other cogs were known in Sweden, and only around 30 are known in the whole of Europe.’
These latest discoveries were made in Summer 2022 outside the medieval town of Getakärr – now the city of Varberg – on the former shoreline and in close proximity to one another.
Archaeologists from Arkeologerna, a part of the country’s Natural Historical Museums authority, in collaboration with Kulturmiljö Halland, Bohusläns Museum, and Visual Archaeology, have been carefully examining the ships and documenting the remains with 3D photogrammetry, uncovering details about how the cogs were constructed.
Along the bottom strakes of both vessels the hull planks had been laid edge to edge, which is known as carvel style. Their sides were crafted in the more traditional clinker style, in which the edges of the hull planks overlap each other.
Dendrochronological analysis has revealed that the larger vessel, measuring 20m long and 6m wide, was built in 1346 with timber felled in a region that today spans the Netherlands, Belgium, and north-eastern France.
The port side of this vessel is mostly complete, making it the best-preserved cog wreck so far identified in Sweden.
The smaller cog, which measures 8m long and 6m wide, was crafted from oak felled c.1355-1357 in northern Poland.
Based on the findings, both ships were foreign guests in Getakärr’s port.
Numerous artefacts have been recovered from the wrecks, among them leather shoes, wooden and ceramic bowls and spoons, barrel lids – some with maker’s marks – and a rare cache of ship equipment and spare parts.
Further studies are underway, as Elisabet explains: ‘We have collected and are analysing soil samples as well, which will hopefully be able to identify the remnants of food and or cargo. We will even search for parasitic remains, which could identify if animals were kept onboard, and if so, which species.’
How the cogs met their fate is still unclear; however, the team to suspect that the larger cog had rolled on to its port side in shallow water while still rigged.
‘Once we have cleaned every timber from the wrecks, and critically analysed them, we will hopefully be able to get to the bottom of the mystery,’ adds Elisabet.