Diverse construction types and local timber sources characterize early medieval church roofs in southwestern Sweden

• Four Romanesque church roofs were dendroarchaeologically investigated.
• Oak and pine were the dominant tree species in the constructions.
• The utilized trees were derived from local woodland sources.
• The felling dates of the trees lie between AD 1131 and 1157.
• The four churches belong to the oldest still standing medieval buildings in Sweden and Europe.

A vast number of early medieval roof structures are still preserved in Swedish churches, yet countrywide surveys and detailed dendrochronological investigations, in tandem with building archaeology, are largely lacking. Here, we present new findings from four parish churches (Forsby, Forshem, Gökhem and Marka) in Västergötland, southwestern Sweden. The roof constructions, made from local oak and pine trees, were dated to the period between AD 1131 and 1157, making these some of the oldest preserved roof structures in Sweden and Europe. With the development of new regional pine and oak tree-ring chronologies covering the 10th to 13th centuries, we open up the discussion about medieval timber technology, wood utilization and the potential for future tree-ring based paleo-environmental exploration.