For more than 1,300 years it stayed hidden in the crystal-clear waters of the Adriatic, off the Croatian island of Mljet (Meleda). Today that Byzantine wreck is returning one of the most extraordinary archaeological treasures ever found in the Mediterranean: over 600 grams of gold, precious buckles adorned with emeralds, rubies, and pearls, imperial coins, and a very rare signet ring that may have belonged to a high-ranking official of the Byzantine Empire.
According to archaeologists, the vessel sank between the late 7th and early 8th centuries while crossing one of the Adriatic’s major trade routes. For the Croatian Institute for Conservation, it represents one of the most significant underwater archaeological discoveries from the Byzantine period ever made in the Mediterranean.
The Treasure Found in the Byzantine Wreck of Mljet
The wreck rests on the seabed near Polače, on the island of Mljet (Croatia), and has been the subject of study since 2015. Since then the Department of Underwater Archaeology of the Croatian Institute for Conservation has conducted nine excavations that have unearthed artifacts of exceptional value. The most spectacular discovery consists of over 600 grams of gold objects, which, according to researchers, represent the largest concentration of gold ever recovered from a wreck dating to the Byzantine period in the Mediterranean.
Among the most precious finds are four refined belts with gold buckles studded with emeralds, rubies, and pearls. These are not mere jewelry: these adornments were part of the ceremonial attire reserved for the empire’s high dignitaries and served to instantly indicate their rank.
What makes the discovery even more exceptional is, above all, a gold signet ring depicting an emperor from the dynasty founded by Heraclius. According to scholars, an object of this kind would have belonged only to a very senior official of the Byzantine administration or army and was used to authenticate official documents. It is this artifact that has reinforced the hypothesis that a person of very high rank traveled aboard the ship—perhaps a military commander, an imperial administrator, or a diplomatic envoy on an official mission.
In addition to the precious items, the wreck has yielded amphorae, ceramics, commercial weights, and other objects meant for trade, suggesting that the vessel carried not only distinguished passengers but also a substantial cargo of goods.
Why This Discovery Is So Important
The significance of the wreck goes far beyond the value of the recovered artifacts. The gold coins found on board, minted under four emperors of the Heraclian dynasty, have allowed archaeologists to date the shipwreck precisely to the late 7th to early 8th century, a particularly delicate period for the Byzantine Empire, confronted with profound political and military changes.
Justin Leidwanger, a Stanford University archaeologist collaborating on the project, described Mljet as “the most important wreck of its period.” For scholars, the site offers a rare testimony to how people, luxury goods, and commodities continued to travel along the Adriatic routes even as the Roman world gradually transformed into medieval Europe.
Experts believe the ship was likely seeking shelter in the natural Polače Bay, long regarded as a safe harbor for mariners. Something, however, prevented its arrival: perhaps a fierce storm, a navigational error, or a structural failure of the vessel.
Nevertheless, the research is far from finished. Specialists are still analyzing amphorae, ceramics, coins, and precious artifacts to reconstruct the vessel’s origin, its itinerary, and the identities of the people who were aboard. Every new find helps to piece together a page of the Byzantine Mediterranean’s history that remains little known, hidden for more than thirteen centuries in the depths of the sea.
