Then Shalmaneser king of Assyria attacked. Hoshea was already a puppet of the Assyrian king and regularly sent him tribute, but Shalmaneser discovered that Hoshea had been operating traitorously behind his back—having worked out a deal with King So of Egypt. And, adding insult to injury, Hoshea was way behind on his annual payments of tribute to Assyria. So the king of Assyria arrested him and threw him in prison, then proceeded to invade the entire country. He attacked Samaria and threw up a siege against it. The siege lasted three years.