According to Menachem Waldman, a major wave of emigration from the Kingdom of Judah to Kush and Abyssinia dates to the Assyrian Siege of Jerusalem, in the beginning of the 7th century BCE. Rabbinic accounts of the siege assert that only about 110,000 Judeans remained in Jerusalem under King Hezekiah's command, whereas about 130,000 Judeans led by Shebna had joined Sennacherib's campaign against Tirhakah, king of Kush. Sennacherib's campaign failed and Shebna's army was lost "at the mountains of darkness", suggestively identified with the Semien Mountains.