Who was Athaliah?

Athaliah was the daughter of the wicked Baal worshiping wife of King Ahab of the Northern Kingdom of Israel, Jezebel.

Through marriage to Jehoram King of Judah who himself 'walked in the ways of the Kings of Israel' she came to high position. When Ahaziah, who was also wicked, died after only one year on the throne, Athaliah plotted to take the throne and had all the royal descendants killed except Joash who had been taken away from the slaughter.

Athaliah thus ruled in Judah from 841-835 BC having usurped the throne. When Joash was old enough he was put onto the throne and Athaliah removed.