Athaliah the mother of Ahaziah: this, and 2 Chronicles 22:11,12, are explained on 2 Kings 11:1-3.
Related Commentaries of 2 Chronicles 22:10
2 Chronicles 22:10
10 But when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal of the house of Judah.