Manasseh was the last king of Isaiah's prophetic reign. Manasseh was a bad king and out of the next 5 kings 1 was good and 4 were bad. They caused Israel to follow false idols and the evil things that Israel had created that caused them to be exiled and so God exiled Judah as well.
Judah was given warning about their ways. Isaiah had warned them that they were on this path a long time ago. During Manasseh's reign they were invaded by Assyria, losing some cities and being forced to pay them a tribute, just as Israel had to do. Eventually Babylon conquered Assyria and put pressure on Judah as well. They would even capture some of their people into slavery but still Judah did not pick up on the signs, despite the prophets warning them.
To show that God was no longer with His rebellious people the Temple was looted by Babylon and destroyed. All the tools for sacrifices of atonement were taken and the Temple burned to the ground. The sign that God was with Israel was destroyed and Israel was without their God and their Promised Land. Jerusalem was laid waste without its walls, Temple, palace, and homes.
For the same reasons Israel was exiled Judah was as well but there was still hope. Just as this prophecy of Isaiah came true so would the other two. God would restore both Israel and Judah to the promised land and unite the two nations into one again. God would also send the Messiah, to establish a new covenant that would prevent such bloodshed and slavery from happening because of the sins of the people.