Sargon took the throne from Shalmaneser, probably in a violent coup.
“In the year that the commander came to Ashdod, when Sargon the king of Assyria sent him and he fought against Ashdod and captured it…” (Isaiah 20:1).
The foreign people brought into Samaria replaced the Israelites. These led to new languages and customs, a pick and mix religion, and the cult of the Samaritans who were hated in the day of Jesus.
“The king of Assyria brought men from Babylon and from Cuthah and from Avva and from Hamath and Sepharvim, and settled them in the cities of Samaria in place of the sons of Israel. So they possessed Samaria and lived in its cities.” (2 Kings 17:24).