In the year that Tartan came unto Ashdod, (when Sargon the king of Assyria sent him,) and fought against Ashdod, and took it;
2 At the same time spake the Lord by Isaiah the son of Amoz, saying, Go and loose the sackcloth from off thy loins, and put off thy shoe from thy foot. And he did so, walking naked and barefoot.
3 And the Lord said, Like as my servant Isaiah hath walked naked and barefoot three years for a sign and wonder upon Egypt and upon Ethiopia;
4 So shall the king of Assyria lead away the Egyptians prisoners, and the Ethiopians captives, young and old, naked and barefoot, even with their buttocks uncovered, to the shame of Egypt. (Isaiah 20:1-4)
Question: Isaiah 20 is generally timestamped in 712/711 BC and if Sargon is the king that sent Tartan and conquered Ashdod as it says in verse 1, did Sargon II ever take Egyptians and Ethiopians into captivity? I can't find any extra-biblical evidence of Assyria conquering Egypt as this prophecy says up until Esarhaddon or Ashurbanipal.