The Old Babylonian Empire, flourishing from around 1894 to 1595 BCE, marks a transformative era in Mesopotamian history. This period is notably defined by the rise and reign of Hammurabi, one of history's most legendary rulers, who ascended the throne in 1792 BCE (or 1728 BCE in short chronology). Hammurabi's reign, lasting until 1750 BCE (or 1686 BCE), was a time of significant expansion and cultural flourishing for Babylon.

One of Hammurabi's earliest and most impactful actions was the liberation of Babylon from Elamite dominance. This victory was not just a military triumph but also a crucial step in consolidating Babylon's independence and setting the stage for its rise as a regional power. Under his rule, Babylon underwent extensive urban development, transforming from a small town into a significant city, indicative of its growing importance and influence in the region.

Hammurabi's military campaigns were pivotal in shaping the Old Babylonian Empire. His conquests extended across southern Mesopotamia, incorporating key cities like Isin, Larsa, Eshnunna, Kish, Lagash, Nippur, Borsippa, Ur, Uruk, Umma, Adab, Sippar, Rapiqum, and Eridu. These victories not only expanded Babylon's territory but also brought stability to a region previously fragmented into a patchwork of small states.

Beyond military conquests, Hammurabi is renowned for his legal code, the Code of Hammurabi, a groundbreaking compilation of laws that influenced future legal systems. Discovered in 1901 at Susa and now housed in the Louvre, this code is one of the oldest deciphered writings of significant length in the world. It showcased advanced legal thought and the emphasis on justice and fairness in Babylonian society.

The Old Babylonian Empire under Hammurabi also saw significant cultural and religious developments. Hammurabi played a key role in elevating the god Marduk, making him supreme in the pantheon of southern Mesopotamia. This religious shift further cemented Babylon's status as a cultural and spiritual center in the ancient world.

However, the empire's prosperity waned following Hammurabi's death. His successor, Samsu-iluna (1749–1712 BCE), faced considerable challenges, including the loss of southern Mesopotamia to the native Akkadian-speaking Sealand Dynasty. The subsequent rulers struggled to maintain the empire's integrity and influence.

The decline of the Old Babylonian Empire culminated with the Hittite sack of Babylon in 1595 BCE, led by King Mursili I. This event not only marked the end of the Amorite dynasty in Babylon but also significantly altered the geopolitical landscape of the ancient Near East. The Hittites, however, did not establish long-term control over Babylon, and their withdrawal allowed the Kassite dynasty to rise to power, thus signaling the end of the Old Babylonian period and the beginning of a new chapter in Mesopotamian history.