In year one of King Darius the Mede, I arose to fortify and strengthen him.'"

in the first year of his reign I, Daniel, noted in the Scripture the total years that were assigned by the message from the LORD to Jeremiah the prophet for the completion of the desolations of Jerusalem: 70 years.

After a number of years, they'll become allies and the daughter of the southern king will go to the northern king in order to craft alliances. But she won't remain in power, nor will he retain his power. Instead, she'll be surrendered, along with her entourage, the one who fathered her, and the one who supported her at that time.