Nabonidus ascended the throne following the assassination of King Labashi-Marduk, marking the end of the Chaldean dynasty's direct line. His reign was characterized by a shift in religious focus, favoring the moon god Sin over the traditional Babylonian patron deity, Marduk. This shift alienated the Babylonian priesthood and contributed to political unrest. Nabonidus's reign also saw significant archaeological activities, including excavations and restorations of ancient temples, which have led some scholars to regard him as an early practitioner of archaeology.

circa 618-539 BCE

Nabonidus was born around 618 BCE in Harran, a city located in present-day southeastern Türkiye. His father, Nabu-balatsu-iqbi, served as a governor, and his mother, Adad-guppi, was an influential Assyrian votary of the moon god Sin. Some scholars suggest that Nabonidus's maternal lineage may have been connected to the Sargonid dynasty of the Neo-Assyrian Empire. His ascent to the throne of Babylon was unconventional; he was not a member of the Chaldean dynasty but was proclaimed king following the assassination of King Labashi-Marduk in 556 BCE.

Nabonidus's reign was marked by his devotion to the moon god Sin, which led to significant religious reforms. He appointed his daughter, Ennigaldi-Nanna, as the high priestess of ancient Ur, reviving an office that had been vacant for centuries. This act not only underscored his religious convictions but also highlighted his efforts to consolidate power through religious authority.

In 552 BCE, Nabonidus embarked on a self-imposed exile to the Arabian oasis of Tayma (in modern day Saudi Arabia). The reasons for this exile remain debated; some scholars speculate it was due to political tensions with the Babylonian priesthood, while others suggest it was a strategic move to secure northern borders and engage in military campaigns. During his absence, his son Belshazzar acted as regent in Babylon. Nabonidus returned to Babylon in 543/542 BCE, where he continued his religious reforms and building projects until the Persian conquest in 539 BCE, which marked the fall of Babylon.

circa 618-539 BCE

Nabonidus's reign is notable for its significant archaeological endeavors, which have provided valuable insights into ancient Mesopotamian history and culture. His archaeological activities were not merely acts of restoration but were deeply intertwined with his religious and political objectives.

One of his most ambitious projects was the restoration of the Ehulhul temple in Harran, dedicated to the moon god Sin. This temple had been destroyed by the Medes in 610 BCE, and Nabonidus's efforts to rebuild it were motivated by both religious devotion and political considerations, aiming to reassert Babylonian influence in the region.

In his quest to restore ancient religious sites, Nabonidus also excavated the Ebabbar temple in Sippar, dedicated to the sun god Shamash. During these excavations, he discovered the foundation stone laid by Naram-Sin, a king from the Akkadian period, which had been lost for over three millennia. This discovery is often cited as an early example of archaeological excavation.

He is believed to have built a residential palace at al-Mubayyat, Tayma, in modern day Saudi Arabia during (circa 552-542 BCE) his self-imposed exile to the oasis town.

Nabonidus commissioned numerous inscriptions and stelae to commemorate his religious and political achievements. Notable among these is the Harran Stela, which records his restoration of the Ehulhul temple and his devotion to Sin. These inscriptions provide valuable insights into his reign and religious practices.

Several cuneiform cylinders were created during Nabonidus's reign, detailing his building projects and religious activities. These cylinders serve as important historical documents, shedding light on the king's archaeological endeavors and his efforts to legitimize his rule through religious reforms.

Nabonidus's archaeological activities were not only acts of restoration but also strategic moves to consolidate power and assert his legitimacy as king. Through these endeavors, he left a lasting legacy that provides modern scholars with a glimpse into the religious and political dynamics of the Neo-Babylonian Empire.