When his brother died in 159 BC, his nephew was too young to rule at the time, so he ascended the throne as regent and married Stratonice once again.
Ketika abangnya meninggal pada tahun 159 SM, keponakannya masih terlalu muda untuk memerintah saat itu, sehingga ia naik tahta sebagai regent (wali) dan sekali lagi menikahi Stratonice.