Artsa was the palace steward (master of the house) of Elah, king of Israel. It was in Artsa's house at Tirzah that Zimri conspired against Elah and assassinated him — initiating one of the Northern Kingdom's violent dynasty changes and fulfilling Jehu's prophecy against the house of Baasha.
The assassination of Elah in Artsa's house illustrates a recurring theme in Kings: dynastic violence and instability in the Northern Kingdom, contrasted with the Davidic dynasty's relative stability in the south. Where God established a covenant with David promising an enduring dynasty, the north experienced rapid and violent succession changes — a theological commentary on the consequences of following Jeroboam's way rather than the covenant of David.