In the fourth year of Hezekiah's reign - which was the seventh year of King Hoshea's reign over Israel - Emperor Shalmaneser of Assyria invaded Israel and besieged Samaria.
In the third year of the siege Samaria fell; this was the sixth year of Hezekiah's reign and the ninth year of Hoshea's reign.
The Assyrian emperor took the Israelites to Assyria as prisoners and settled some of them in the city of Halah, some near the Habor River in the district of Gozan, and some in the cities of Media.
References for 2 Kings 18:11
Samaria fell because the Israelites did not obey the Lord their God, but broke the covenant he had made with them and disobeyed all the laws given by Moses, the servant of the Lord. They would not listen and they would not obey.