Archaeologists have discovered an exceptional Christian artifact in Austria that is thought to be around 1,500 years old.

The artifact in question is heavily fragmented, but researchers said the pieces once formed a type of round container known as a "pyx" that in this case was made of ivory and richly decorated with Christian motifs.

The pyx was found at the site of a 5th-6th century church during excavations at a hilltop settlement from late antiquity, now located in the municipality of Irschen, southern Austria, archaeologists from the University of Innsbruck have announced.

Gerald Grabherr, the leader of the Innsbruck archaeological team, told Newsweek that the circumstances of the discovery are "unique."

Only around 40 ivory boxes of this kind are known worldwide and the last time one was found during excavations was around 100 years ago.

Such objects are almost never found in their original archaeological contexts. The few that do exist tend to be preserved in cathedral treasuries or exhibited in museums, according to Grabherr. But the example from Irschen was found within a marble shrine hidden under the altar in the side chapel area of the 5th-6th century church. As such, it is the first pyx of this kind to be found in its archaeological context in Austria, the researcher said.

This type of reliquary box was usually removed when a church was abandoned because they were considered to be particularly sacred. But in this case, it was left behind.

Grabherr told Newsweek the pyx may have originally been used to hold sacred items, such as the relics of a saint. The way in which the fragments of the pyx were layered in the marble shrine, however, indicate that the container was already broken in late antiquity and was buried in this state.

"The pyx was presumably also seen as sacred and was treated as such because it was in contact with a relic. The archaeological and art-historical significance of the pyx cannot be denied," Grabherr said in a press release.

The decorations on the pyx depict a variety of biblical scenes. For example, on one section, a man can be seen at the foot of a mountain. The individual is shown turning his gaze away while a hand is visible rising out of the sky above him, placing something between his arms.

"This is the typical depiction of the handing over of the laws to Moses on Mount Sinai, the beginning of the covenant between God and man from the Old Testament," Grabherr said.

In another section, a man is depicted on a chariot with two horses harnessed to it. Again a hand is visible coming out of the clouds, but this time it is pulling the figure up into heaven.

"We assume that this is a depiction of the ascension of Christ, the fulfilment of the covenant with God," Grabherr said. "The depiction of scenes from the Old Testament and their connection with scenes from the New Testament is typical of late antiquity and thus fits in with our pyx; however, the depiction of the Ascension of Christ with a so-called 'biga'—a two-horse chariot—is very special and previously unknown."

The pyx is in a very fragile state because ivory tends to absorb moisture from its surroundings, which has turned the material very soft over time. Ulrike Töchterle, head of the restoration workshop at Innsbruck, has been working to conserve the artifact since its discovery—and it is now in a condition where it can be scientifically analyzed.

The hilltop settlement where the pyx was found was established in the late 3rd or early 4th century when the region was still part of the Roman Empire, according to Grabherr. It appears to have been abandoned around the year 610 and had largely been forgotten until the Innsbruck team began carrying out excavations at the site in 2016.

These excavations have uncovered the remains of a number of dwellings, two Christian churches and a cistern—a space excavated for the purpose of storing water.

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