WHO WAS ATHALIAH?

Athalia (afflicted of the Lord) is the only woman in the Hebrew Scripture reported as having reigned as a monarch within Israel/Judah. She managed to remain sole monarch for 6 years. In the 7th year a revolution led by Jehoiada the High Priest puts on the Throne the 7-year-old Joash, Ahaziah's child who was rescued by his paternal aunt and Jehoiada's wife, from the royal bloodbath 6 years earlier.
Athalia, who walked in the ways of the House of Ahab, and called "daughter of Omri," was the Queen consort of Judah as the wife of King Jehoram, son of the pious Jehoshaphat king of Judah, descendant of King David, and later Queen regnant. As Queen, she used her power and her pernicious influence to establish the worship of Baal in Judah and drew into idolatry and crime both her husband and her son Ahaziah.
Athalia, born in Samaria, was the daughter of King Ahab and Queen Jezebel of Israel and granddaughter of Omri, the 6th king in line of the Northern 10-Tribe kingdom. Nothing of Omri's ancestry is recorded. She was the sister of Israel's King Jehoram, and full or half sister of the other 70 sons of Ahab.
Athalia was given in a marriage of political expediency to Jehoram the eldest son of Jehoshaphat of Judah to seal a "treaty" between the kingdoms of Israel and Judah. To secure his position Jehoram killed his 6 brothers, married Athalia and reigned for 8 years. Athalia became the mother of Ahaziah, who in time became king of Judah.
Like her mother Jezebel, Athalia egged on her husband Jehoram to do what was bad in God's eyes during his reign. And like her mother, she wantonly shed the blood of the innocent. Jehoram's rule was shaky. Edom revolted, and he was forced to acknowledge their independence. A raid by Philistines, Arabs, and Ethiopians looted the king's house, and carried off all of his family except for their youngest son, Ahaziah.
After Jehoram's death, her wicked son Ahaziah became king of Judah, and Athalia was Queen mother. He reigned for one year from the age of 22 and was killed during a state visit to Israel along with Jehoram of Israel, Athalia's brother. Jehu assassinated them both in God's Name, together with the other 70 sons of Ahab, and became king of Israel. He had Athalia's entire extended family in Israel put to death, ending Omri dynasty.
For her part, after the premature death of her son and the great revolution by which Jehu seated himself on the throne of Samaria, Athalia seized the throne of Judah, and sought to secure herself in it by ordering the execution of all possible claimants to the throne, including the remnant of her Omri dynasty. However, Jehosheba, Ahaziah's sister, managed to rescue from the purge one of Athalia's grandsons with Jehoram of Judah, named Jehoash, who was only one year old.
Jehoash was raised in secretly by Jehosheba's husband, a bold and faithful high priest named Jehoiada. At length the high priest Jehoiada thought it time to produce the lawful king to the people, trusting to their zeal for the Worship of God and their loyalty to the House of David.
Thereupon Athalia installed herself as Queen for 6 years. During this time she robbed God's temple of the Holy Things and offered them to Baal.
When Jehoash reached 7 years of age, God-fearing high priest Jehoiada brought the lad out of secrecy from the place of refuge, and crowned him rightful heir to the Throne. Jehoiada's plan was successful.
Hearing the tumult, Athalia rushed to the Temple to stop the rebellion and upon seeing what was happening, cried, "Conspiracy! Conspiracy!" She was surprised when Jehoiada revealed that Jehoash lived and proclaimed him king of Judah. Then High Priest Jehoiada ordered the blood-stained Athalia to be taken outside the Temple grounds to be executed at the Horse Gate of the palace.
How true it proved to be the God's prophecy: "Nothing of God's Word will fall unfulfilled to the earth that God has spoken against the House of Ahab." 2 Kings 10:10, 11.