Complex sentence: The House of Crnojević was a dynasty ruling in the Medieval Serbian state of Zeta, first struggling with House of Balša for control over Zeta, and then succeeding them as Zeta's supreme overlords throughout the 14th and 15th century.
Split into simpler sentences: The House of Crnojević was a dynasty ruling in the Medieval Serbian state of Zeta. At first it was struggling with House of Balša for control over Zeta and then succeeding them as Zeta's supreme overlords throughout the 14th and 15th century.