Ancient Babylon was ruled by a series of monarchs or kings dating back to thousands of years before the birth of Jesus.  One of the earliest and most well-known rulers of ancient Babylon was Hammurabi, whose rule is dated from about 1792 B.C. when he seized the throne from his father, Sin-Muballit, to his death in 1750 B.C.  Hammurabi is credited as having begun the formation of the Babylonian Empire, one of the greatest empires in human history.  His military conquests unified Mesopotamia (principally modern day Iraq) under Babylonian rule.  Among Hammurabi's greatest accomplishments, though, was his establishment of what is known today as "Hammurabi's Code," possibly the earliest formal effort at establishing a legal structure for governing.  A series of 282 laws, "Hammurabi's Code" continue to be referenced today as a model legal framework in which a society can function under the rule of law.

Hammurabi was succeeded following his death by his sons, but under their rule the empire began to decline until the reign of King Nebuchadenezzar II, who was instrumental in restoring the Babylonian Empire's glory.  Under Nebuchadenezzar II, who ruled from about 605 B.C. to 562 B.C., the empire expanded to included territory stretching all the way to the Mediterranean Sea.  Babylon became the center of civilization (at least within the geographical restrictions of the region known today as "the Middle East") and its prominent role in both scientific and Biblical history is unparalled.  

While the Babylonian Empire would eventually be replaced by succeeding empires, rule over these territories continued to be primarily by monarchies, a trend that would last for thousands of years.