The Assyrian conquest of Egypt covered a relatively short period of the Neo-Assyrian Empire from 673 to 663 BCE. The conquest of Egypt not only placed a land of great cultural prestige under Assyrian rule but also brought the Neo-Assyrian Empire to its greatest extent.
Context
The Egyptians and Kushites had begun agitating peoples within the Assyrian empire in an attempt to gain a foothold in the region. As a result, in 701 BCE, Hezekiah of Judah, Lule king of Sidon, Sidka, king of Ascalon and the king of Ekron formed an alliance with Egypt against Assyria. The Neo-Assyrian ruler Sennacherib (705–681 BC) attacked the rebels, conquering Ascalon, Sidon and Ekron and defeating the Egyptians and driving them from the region. He marched toward Jerusalem, destroying 46 towns and villages (including the heavily defended city of Lachish) in his path. This is graphically described in Isaiah 10; exactly what happened next is unclear (the Bible says an angel of the Lord killed 185,000 Assyrian soldiers at Jerusalem after Hezekiah prayed in the temple). There are various theories (Taharqa's army, disease, divine intervention, Hezekiah's surrender, Herodotus' mice theory) as to why the Assyrians failed to take Jerusalem and withdrew to Assyria. Sennacherib's account says Judah paid him tribute and he left.
In 681 BCE, Sennacherib was murdered while praying to the god Nisroch by one or more of his own sons (allegedly named Adremelech, Abimlech, and Sharezer), perhaps as retribution for his destruction of Babylon.
Invasion of Esarhaddon (673 BCE)
Esarhaddon (ruled 681–669 BCE), the son of Sennacherib, led several campaigns against Taharqa of Egypt, which he recorded on several monuments. His first attack in 677 BCE, aimed at pacifying Arab tribes around the Dead Sea, led him as far as the Brook of Egypt.
Campaign of 673 BCE
Esarhaddon then raided Egypt in 673 BCE. This invasion, which only a few Assyrian sources discuss, ended in what some scholars have assumed was possibly one of Assyria's worst defeats. Taharqa and his army defeated the Assyrians outright in 674 BC, according to Babylonian records. The Egyptians had for years sponsored rebels and dissenters in Assyria and Esarhaddon had hoped to storm Egypt and take this rival out in one fell swoop. Because Esarhaddon had marched his army at great speed, the Assyrians were exhausted once they arrived outside the Egyptian-controlled city of Ashkelon, where they were defeated by the Kushite Pharaoh Taharqa. Following this defeat, Esarhaddon abandoned his plan to conquer Egypt for the moment and withdrew back to Nineveh.
Campaign of 671 BCE
Two years later Esarhaddon launched a full invasion. In the early months of 671 BC, Esarhaddon again marched against Egypt. The army assembled for this second Egyptian campaign was considerably larger than the one Esarhaddon had used in 673 and he marched at a much slower speed in order to avoid the problems that had plagued his previous attempt. On his way he passed through Harran, one of the major cities in the western parts of his empire. Here, a prophecy was revealed to the king, which predicted that Esarhaddon's conquest of Egypt would be a successful one. According to a letter sent to Ashurbanipal after Esarhaddon's death, the prophecy was the following:
Three months after having received this prophecy, Esarhaddon's forces were victorious in their first battle with the Egyptians. Despite the prophecy and initial success, Esarhaddon was not convinced of his own safety. Just eleven days after he had defeated the Egyptians, he performed the "substitute king" ritual, an ancient Assyrian method intended to protect and shield the king from imminent danger announced by some sort of omen. Esarhaddon had performed the ritual earlier in his reign, but this time it left him unable to command his invasion of Egypt.
In 671 BCE Esarhaddon took and sacked Memphis, where he captured numerous members of the royal family. Although the Pharaoh Taharqa had escaped to the south, Esarhaddon captured the Pharaoh's family, including his son and wife, and most of the royal court, which were sent back to Assyria as hostages. Esarhaddon reorganized the political structure in the north, governors loyal to the Assyrian king were placed in charge of the conquered territories, and he established Necho I as king at Sais. Upon Esarhaddon's return to Assyria he erected a stele alongside the previous Egyptian and Assyrian Commemorative stela of Nahr el-Kalb, as well as a victory stele at Zincirli Höyük, showing Taharqa's young son Ushankhuru in bondage.