II Chronicles - Chapter 22
Coup #1 – Atalyahu’s In
Achazyahu also chose to follow in Ahab's evil ways. His mother was the daughter of Omri, another wicked king of the Ten Tribes, and the influence of Ahab's dynasty led to Achazyahu's downfall.
Yehoram, king of the northern kingdom, was wounded in battle, so Achazyahu went to pay him a visit. While there, he joined Yehoram in a campaign against a man named Yehu, who had been anointed by a prophet in order to oust the family of Ahab from the throne. Yehu sought out and executed Ahab's descendants and he went after Achazyahu, who was in town.
Yehu's forces found Achazyahu and brought him to their leader. Yehu executed him without fear of retaliation, since Achazyahu's sons were all too young to succeed him. When Achazyahu's mother, Atalyahu, learned that her son had been killed, she decided to seize the throne and eliminate her grandsons. However, her daughter Yehoshavas took Yoash, the one surviving prince, and hid him away. Yehoshavas was married to Yehoyada the kohein, so she had Yoash hidden in the Temple for six years while Atalyahu ruled.