In an archaeological expedition along the Baltic Sea coastline of the Swedish city of Kalmar, researchers have unearthed a unique collection of ancient artefacts, including a gold ring embellished with an engraving of Jesus Christ's face.

The findings, part of a two-year excavation project in the city's Old Town, are said to have "exceeded all expectations".

Since the 13th century and until the mid-17th century, Kalmar's Old Town was a bustling hub of activity. The current dig has explored around 50 medieval plots, ten streets, and sections of the Old City wall in an effort that surpasses previous excavations in other European old towns.

Archaeologists anticipated some discoveries but were "astounded" by the sheer volume and significance of the relics found.

The cache included remnants of hundreds of buildings, cellars, streets, latrines, and objects that date back to 1250-1650.

Magnus Stibéus, the lead archaeologist on the project said in a statement: "We have managed to expose the city's middle ages and study how people lived, what they ate and drank and how this changed over time. Archaeology provides us with a window into medieval history that allows us to learn more about life several hundred years ago".

Among an impressive haul of 30,000 identified artefacts were two "spectacular" finds: the gold ring featuring an engraving of Jesus Christ's face and a unique artefact known as an 'alsengem'.

The ring is believed to be from the early 15th century and archaeologicalists believe its petite size means it was likely worn by a woman.

The alsengem is a form of small glass setting stone used in secular and religious contexts. It is thought to have been utilised by pilgrims as amulets during the 13th to 14th centuries. The piece found at Kalmar is decorated with three carved figures.

"The gold ring was almost brand new with a Christ motif and was discovered, like the alsengem, in contexts that we interpreted as waste storage. Probably someone was unlucky and lost the ring 500 years ago. The alsengem is broken and may have been discarded," Stibéus said.