Found in northern Saudi Arabia, the inscription depicts sixth-century B.C.E. ruler Nabonidus holding a scepter

Researchers in Saudi Arabia have discovered a sixth-century B.C.E. rock carving of the last Babylonian king, Nabonidus.

As Arab Newsreports, archaeologists from the Saudi Commission for Tourism and National Heritage spotted the 2,550-year-old inscription engraved on a basalt stone in the Al-Hadeed Governorate, in the country’s northern Hail region.

Per a statement, the carving contains 26 lines of cuneiform writing, making it the longest cuneiform inscription discovered in Saudi Arabia to date. The find could shed light on the history of the Arabian Peninsula and its ancient residents’ ties to neighboring Mesopotamia.

The etching shows the Babylonian king standing with a scepter in his hand. Four symbols—a crescent moon, the sun, a snake and a flower—hover in front of him.

Scholars suspect that these images hold religious significance but are still comparing the carving with similar ones to determine its meaning, notes Arab News. According to the History Blog, the markings may be linked to deities in the Mesopotamian pantheon, representing the star of Ishtar, the winged disc of the sun god Shamash and the crescent of the moon deity Sin.

Experts found the inscription in the town of Al Hait. Known as Fadak in ancient times, Al Hait is home to the ruins of fortresses, rock art and water installations, writes Owen Jarus for Live Science.

The site holds “great … significance,” boasting an early history that spans the first millennium B.C.E. through the beginning of the Islamic era, notes the commission on Twitter. Researchers in the area have previously discovered inscriptions and obelisks mentioning Nabonidus, who ruled Babylonia from 556 to 539 B.C.E., when the kingdom fell to Cyrus of Persia, reports Arab News.

At its height, the Babylonian Empire stretched from the Persian Gulf to the Mediterranean Sea. When Nabonidus began his reign, he conquered portions of what is now Saudi Arabia. Four years after assuming power, the king named his son Belshazzar coregent and went into exile in Tayma, a city some 160 miles north of Al Hait. He remained there until around 543 B.C.E., per Live Science.

Historians are unsure why Nabonidus left Babylon, but as Arkeonewspoints out, his “self-imposed exile from political and religious authority” may have been the result of a coup.

Disputes between the clergy and Babylon’s elite could also have led to the king’s departure. According to the History Blog, Nabonidus attempted to change his people’s religious hierarchy by declaring the moon god superior to all other deities—a move that may have aggravated the nobility.

Much about the last Babylonian king—including his fate following the fall of Babylon—remains unknown. Enyclopedia Britannica suggests that he was captured by one of Cyrus’ generals and exiled.