During the United Kingdom: first Saul is king, then David, then Solomon. But after that, once we have the Kingdom of Judah in the south and the Kingdom of Israel in the north, things get fuzzy really fast. Between Saul’s coronation and the days when the last of Judah was conquered by Babylon and sent into exile, about 433 years passed and they had 42 kings and 1 illegitimate queen. That’s a lot of people to keep track of, particularly when a lot of them have very similar sounding names.
The background of our story is that several kings of Judah have died pretty quickly one right after the other. Jehoshaphat – who never jumped in the Bible, by the way – Jehoshaphat was a mostly good king who followed the ways of the Lord. But he thought it would be good to strengthen ties with the northern kingdom – the kingdom of Israel – by seeking a marriage between his son Jehoram and their daughter Athaliah. Now, Athaliah was the daughter of Ahab and Jezebel. And they were wicked rulers – the Bible even calls Ahab “the troubler of Israel” and “more evil than all the kings before him.” To secure political alliances with the Phoenicians, Ahab had married Jezebel, daughter of the king of Tyre who was a HUGE, MASSIVE, ENTHUSIASTIC worshipper of Baal and Ashteroth. In her culture, the queen was deeply involved in overseeing religious ritual and practice so she insisted that Ahab build a temple and an altar for Baal. She tried to convert the entire kingdom of Israel to Baal worship and rounded up and slaughtered all the prophets of the Lord that she could get her hands on. Ahab was very much influenced by her.
Enter Athaliah: in every way, she was her mother’s daughter. In her marriage to Jehoram, the family secured influence over the kingdom of Judah, too. When Jehoram died because of wounds he received in battle, their son Ahaziah became the 6th king of Judah. Athaliah and her family convinced him to join the northern kingdom in their battle against the Arameans. At this time, the prophet Elisha sent a disciple to anoint a new king in Israel – a king who would follow God’s ways and remove the worship of Baal from the land. That man was called Jehu. With great violence, he called the northerners together to clean house and slew all of the family of Ahab and Jezebel– this included killing Athaliah’s son Ahaziah.
This is where our story begins: Athaliah sees the destruction of her family and the challenge to her religion, Jehosheba (our main focus) is her child who is married to Jehoiada, the High Priest of the Lord God. And there are still many offspring of Ahaziah who have a legitimate claim to the throne. Hear now the word of the Lord.
Source: https://en.wikipedia.org/wiki/Kings_of_Israel_and_Judah