The Babylonian priest Berossus, writing in about 290 BC and quoted later by Josephus, attributed the gardens to the Neo-Babylonian king Nebuchadnezzar II, who ruled between 605 and 562 BC.

There are definitely two and possibly three mortals who are granted eternal life in the epic. The first two are Utnapishtim and his wife.

It is unclear whether Utnapishtim's boatman is also immortal. He certainly lives in the magical subterranean realm of the Apsu with the two flood survivors and is apparently banished from this realm by his master because he has helped a mortal reach there. It is interesting to note that, according to Berossus, the flood hero's pilot went with him when was granted immortality and taken to the realm of the gods.

Nebuchadnezzar was the oldest son and successor of Nabopolassar,who delivered Babylon from its three centuries of vassalage to its fellow Mesopotamian state, Assyria, and in alliance with the Medes, Persians, Scythians, and Cimmerians, laid Nineveh in ruins. According to Berossus, some years before he became king of Babylon, Babylonian dynasties were united. There are conflicting accounts of Nitocris of Babylon being either his wife or daughter. Nabopolassar was intent on annexing the western provinces of Syria (ancient Aram) from Necho II (whose own dynasty had been installed as vassals of Assyria, and who was still hoping to help restore Assyrian power), and to this end dispatched his son westward with a large army. In the ensuing Battle of Carchemish in 605 BC, the Egyptian andAssyrianarmy was defeated and driven back, and the region of Syria and Phoenicia were brought under the control of Babylon. Nabopolassar died in August that year, and Nebuchadnezzar returned to Babylon to ascend the throne. After the defeat of the Cimmerians and Scythians, previous allies in the defeat of Assyria, Nebuchadnezzar's expeditions were directed westward. The powerful Median empire lay to the north. Nebuchadnezzar's political marriage to Amytis of Media, the daughter of theMedianking, had ensured peace between the two empires.

Traditionally they were said to have been built in the ancient city of Babylon, near present-day Hillah, Babil province, in Iraq. The Babylonian priest Berossus, writing in about 290BC and quoted later by Josephus, attributed the gardens to the Neo-Babylonian king Nebuchadnezzar II, who ruled between 605 and 562 BC. Awkwardly, there are no extant Babylonian texts which mention the gardens, and no definitive archaeological evidence has been found in Babylon. According to accounts, the gardens were built to cheer up Nebuchadnezzar's homesick wife, Amyitis. Amyitis, daughter of the king of the Medes, was married to Nebuchadnezzar to create an alliance between the two nations. The land she came from, though, was green, rugged and mountainous, and she found the flat, sun-baked terrain of Mesopotamia depressing. The king decided to relieve her depression by recreating her homeland through the building of an artificial mountain with rooftop gardens.