A bronze signet ring depicting the Lighthouse of Alexandria, a wonder of the ancient world, has been discovered underwater in the Mediterranean off Alexandria, Egypt.

A joint team from the European Institute for Underwater Archaeology (IEASM) and the Egyptian Ministry of Tourism and Antiquities found the artifact in the remains of a palace on the now-submerged island of Antirhodos, marking the first time a signet ring featuring the image of the lighthouse has been found, the IEASM team said in a statement.

The image on the ring is similar to depictions of the lighthouse that have been previously found on coins dating to the second century, representatives of IEASM said.

"The discovery of the ring-signet is even more important as it has been excavated in the legendary palace of the Island of Antirhodos, that once was a centre of power," Franck Goddio, president of IEASM, said in the emailed statement.

The palace was used by Egyptian pharaohs who reigned during the Ptolemaic period (304 to 30 B.C.), a dynasty of rulers descended from one of Alexander the Great's generals. The lighthouse was built on the island of Pharos around 280 B.C. and stood more than 328 feet (100 meters) tall. Some ancient writers, such as Pliny the Elder, considered it among the wonders of the world, and it continued to be used into the Middle Ages, until earthquakes and erosion resulted in its destruction and disappearance beneath the sea.

While the lighthouse was modified over time, it would have had a statue, possibly of Zeus, at the top holding an oil lamp that helped guide mariners.

Whoever was wearing a signet ring could have used it to make an impression on soft materials, such as clay and wax, to create a seal. The discovery of the ring in the remains of the palace at Antirhodos suggests that the palace was used for administrative functions related to the lighthouse, representatives of IEASM said in the statement.

Even though the ring's engraving is somewhat worn, it likely depicts the lighthouse, said Doris Behrens-Abouseif, a professor emeritus of history of art and archaeology at the University of London who has written about the lighthouse but was not part of the research team.

There are "thousands of coins from Alexandria showing a similar depiction of the lighthouse," she told Live Science in an email. Those coins date to the Ptolemaic or Roman (29 B.C. to A.D. 395) periods, she noted.

Behrens-Abouseif added that she wasn't familiar enough with rings from Alexandria to comment on whether this is the only ring that contains this image.

Other scholars told Live Science that they, too, believe that this ring depicts the lighthouse, with two scholars noting that it may feature smoke coming from a lamp at top.

The "most interesting thing about the new signet ring engraved gem is an asymmetrical feature at its peak," which "may depict a plume of smoke from the oil lamp in the hand of the crowning statue," Andrew Chugg, an independent researcher who wrote the book "The Pharos Lighthouse in Alexandria: Second Sun and Seventh Wonder of Antiquity" (Routledge, 2024), said in an email.

Margaret Miles, a professor emeritus of art history and classics at the University of California, Irvine, also noticed the possible plume of smoke. Miles noted in an email that this "ring could have been used as a signet ring by a merchant from Alexandria who used the profile of the [lighthouse] to signal his location in Alexandria. The lighthouse was famous, so it became a symbol of the city."

Research off the coast of Alexandria over the past few years, including the discovery of 22 massive blocks, has revealed more information about the lighthouse, including how exactly it looked, which is helping researchers who are trying to digitally reconstruct it.

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The ancient Egyptians practiced human sacrifice around 5,000 years ago, a period shortly after the country was first unified, a new study finds.

In the new study, Roselyn Campbell, an anthropology researcher at Purdue University, re-examined 46 skulls from individuals who were buried near royal tombs that belonged to King Djer, King Djet and Meretneith (a woman who likely ruled Egypt at times), and were built near the ancient sacred city of Abydos. All three rulers lived during the first dynasty, a period that started around 5,000 years ago when Upper Egypt and Lower Egypt were unified into one kingdom. The sacrificed retainers were buried next to the tomb of the king they had served.

Researchers first excavated the royal burial site in the early 20th century. At the time, the excavator, Flinders Petrie, believed that the hundreds of other burials found near the royal tombs contained nonroyals, such as retainers and other people who served the king. Moreover, it appeared that these nonroyals had been sacrificed after the king they had served died, in the belief that they could serve the king in the afterlife.

However, Petrie was unable to identify evidence of fatal skeletal trauma, and his idea that they were sacrificed has been debated ever since. Petrie reburied most of the human remains, but 46 skulls were retained and preserved in the Duckworth Collections at the University of Cambridge.

In the new study, published Monday (Oct. 5) in the journal Frontiers in Environmental Archaeology, Campbell re-examined these 46 skulls using modern forensic techniques and information about the marks that different types of trauma leaves on human skeletons. Campbell found that 18 of the skulls have signs of trauma that were likely fatal — indicating that these individuals were likely sacrificed, according to a statement from the journal. Specifically, Campbell found that many of the skulls had linear fractures, which Petrie had mistaken for damage that occurred after burial.

Linear fractures "occur when the cranium strikes or is struck by a relatively large object with low overall force; because of the cranium's globular shape, the impact of the blow disperses across the cranial vault," Campbell wrote in the study. "While linear fractures are not always immediately lethal, they often cause intracranial lesions and/or hemorrhage, which can quickly cause loss of consciousness and death if surgery [to relieve pressure] is not performed."

Campbell told Live Science in an email that it's difficult to identify the weapon or object that was used. "Based on comparative forensic and archaeological studies, the most likely implement would have been flat and relatively light, probably made out of something like wood rather than stone," she said.

The practice of human sacrifice seems to have ended in the second dynasty of Egypt. Evidence for human sacrifice is limited and seems to be confined mainly to the first dynasty. Petrie theorized that they were retainers to the king based on the fact that some were buried with gravestones that had titles such as seal-bearer which suggested that they served the king.

"As far as we can tell, this particular type of retainer sacrifice seems to have ended with the close of the First Dynasty, which means it [lasted] around two centuries or possibly less," Campbell said.

Jacobus van Dijk, an Egyptologist at Groningen University in the Netherlands who was not involved with the study, welcomed the new research. The "existence of retainer sacrifice in early Egypt has always been controversial and Dr Campbell's research adds an important argument in support of scholars who, like myself, believe this custom was practised in Egypt in the early dynastic period," he told Live Science in an email.

He noted he was surprised at the method used for human sacrifice, because depictions of ritual killing on wooden labels "seems to indicate that the victim was kneeling with his hands tied behind his back being stabbed in the chest with a knife."

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