king. Nabopolassar was unable to utterly secure Babylonia, and for the next four years he was forced to contend with an occupying Assyrian army encamped in Babylonia trying to unseat him. However, the Assyrian king, Sin-shar-ishkun was plagued by constant revolts among his people in Nineveh, and was thus prevented from ejecting Nabopolassar. The stalemate ended in 615 BC, when Nabopolassar entered the Babylonians and Chaldeans into alliance with Cyaxares, an erstwhile vassal of Assyria, and king of the Iranian peoples; the Medes, Persians, Sagartians and Parthians. Cyaxares had also taken advantage of the Assyrian destruction of the formerly regionally dominant pre-Iranian Elamite and Mannean nations and the subsequent anarchy in Assyria to free the Iranic peoples from three centuries of the Assyrian yoke and regional Elamite domination. The Scythians from north of the Caucasus, and the Cimmerians from the Black Sea who had both also been subjugated by Assyria, joined the alliance, as did regional Aramean tribes. In 615 BC, while the Assyrian king was fully occupied fighting rebels in both Babylonia and Assyria itself, Cyaxares launched a surprise attack on the Assyrian heartlands, sacking the cities of Kalhu (the Biblical Calah, Nimrud) and Arrapkha (modern Kirkuk), Nabopolassar was still pinned down in southern Mesopotamia and thus not involved in this breakthrough. From this point on the coalition of Babylonians, Chaldeans, Medes, Persians, Scythians, Cimmerians and Sagartians fought in unison against a civil war ravaged Assyria. Major Assyrian cities such as Ashur, Arbela (modern Irbil), Guzana, Dur Sharrukin (modern Khorsabad), Imgur-Enlil, Nibarti-Ashur, Gasur, Kanesh, Kar Ashurnasipal and Tushhan fell to the alliance during 614 BC. Sin-shar-ishkun somehow managed to rally against the odds during 613 BC, and drove back the combined forces ranged against him. However, the alliance launched a renewed combined attack the following year, and after five years of fierce fighting Nineveh was sacked in late 612 BC after a prolonged siege, in which Sin-shar-ishkun was killed defending his capital. House to house fighting continued in Nineveh, and an Assyrian general and member of the royal household, took the throne as Ashur-uballit II (612–605 BC). He was offered the chance of accepting a position of vassalage by the leaders of the alliance according to the Babylonian Chronicle. However, he refused and managed to successfully fight his way out of Nineveh and to the northern Assyrian city of Harran in Upper Mesopotamia where he founded a new capital.