Prince of Persia
The Sultan lived and governed over Prince who had an only daughter. When the Sultan left his kingdom to fight in a foreign land, his daughter fell in love with a young traveler visited her at the palace.
This did not please the Sultan's grand Vizier, Jaffar, who meant to marry the Princess himself. In the Sultan's absence, Jaffar attempted to seize the power of his thrown. He kidnapped the Princess and ordered that the Prince be thrown into the dungeons.
Prince of Persia 2: The Shadow and the Flame
Following Jaffar's death at the hands of the Prince, the Sultan offered to give the Prince one reward. The Prince asked for his daughter's hand in marriage and the Sultan allowed them to be married.
Prince of Persia 3D
The Sultan and the Prince are visiting the Sultan's brother, Assan. Soon enough, the Prince's personal body guards are killed by Assan's men. The Prince's was locked in the dungeon and the Sultan was taken by Assan.
Assan kidnapped the Sultan's daughter, the Princess and revealed that the Sultan of Persia promised Assan many years ago that his daughter would marry his son, Rugnor. The Prince manages to find the two, but Assan accidentally killed the Sultan with the blade meant for the prince. Before the Sultan dies, he reveals the location of where his daughter was taken to by Assan and Rugnor.