Merodach-baladan is stated to have entered Babylon and proclaimed himself king at the time of the accession of Sargon II to the Assyrian throne. Merodach-baladan had the support of the Elamites in this action, and although Sargon soon endeavored to dislodge him from Babylon, the Chaldean was able to maintain his position there for a period of about 12 years, according to the Babylonian King List.

The Babylonian King List shows a second reign of nine months (Polyhistor says six months) by “Mardukaplaiddin” as king of Babylon during the second year after Sargon’s death. This is generally accepted as referring to the same king making a second effort to establish himself on the throne of Babylon. It is to be noted, however, that the Babylonian inscriptions in this case refer to him as “Mardukaplaiddin, a native of Habi,” in contrast with “Mardukaplaiddin, [of the] dynasty of the Sea Country,” in the case of the earlier reign. (Ancient Near Eastern Texts, edited by J. Pritchard, 1974, p. 272) This second reign was very short, as Assyrian King Sennacherib quickly occupied Babylon, and Merodach-baladan had to seek refuge in Elam, where he seems to have ended his ambitious career.