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(CNN)When archaeologists uncovered the burial site of two brothers who lived during the 15th century BC in Israel, they were surprised to discover that one of them had brain surgery shortly before he died.
The finding marks the earliest example of trephination, a type of cranial surgery, found in the ancient Near East.
Trephination, also known as trepanation, involves cutting a hole in the skull — and there are examples of the medical procedure dating back thousands of years.
The remains of the brothers, who lived during the Bronze Age between 1550 BC and 1450 BC, were found during an excavation of a tomb in the ancient city of Tel Megiddo.
The older brother, estimated to be between 20 and 40 years old, had angular notched trephination. His scalp was cut and then a sharp, beveled-edge instrument was used to make four intersecting lines on the frontal bone of the skull that made a 30-millimeter (1.2-inch) square-shaped hole.
A study detailing the findings published Wednesday in the journal PLOS ONE.
"We have evidence that trephination has been this universal, widespread type of surgery for thousands of years," said study author Rachel Kalisher in a statement. She is a doctoral candidate at Brown University's Joukowsky Institute for Archaeology and the Ancient World in Providence, Rhode Island.
"But in the Near East, we don't see it so often — there are only about a dozen examples of trephination in this entire region. My hope is that adding more examples to the scholarly record will deepen our field's understanding of medical care and cultural dynamics in ancient cities in this area."
Skull pieces removed during the surgery were included in the brother's grave.
Oddly enough, the bone pieces removed from the skull were included in the grave — but it wasn't the only unusual discovery made about the brothers as researchers studied their bones.
Bronze Age brothers
The city of Tel Megiddo was part of the Via Maris 4,000 years ago. This crucial land route connected Egypt, Syria, Mesopotamia and Anatolia, according to study coauthor Israel Finkelstein, director of the University of Haifa's School of Archaeology and Maritime Cultures.
Tel Megiddo controlled part of this trade route, making it a wealthy and cosmopolitan city full of palaces, temples and fortifications.
"It's hard to overstate Megiddo's cultural and economic importance in the late Bronze Age," Finkelstein said.
The tomb was found in an area adjacent to a late Bronze Age palace in Tel Megiddo, leading researchers to believe the two men were either high-ranking elite members of society or perhaps even royals. DNA testing revealed the two were related and likely brothers.
The men were buried with Cypriot pottery, food and other valuable possessions similar to those found in other local high-status tombs.