Before he died, Bolesław III Wrymouth divided the country, in a limited sense, among four of his sons. He made complex arrangements intended to prevent fratricidal warfare and preserve the Polish state's formal unity, but after Bolesław's death, the implementation of the plan failed and a long period of fragmentation was ushered in. For nearly two centuries, the Piasts would spar with each other, the clergy, and the nobility for the control over the divided kingdom. The stability of the system was supposedly assured by the institution of the senior or high duke of Poland, based in Kraków and assigned to the special Seniorate Province that was not to be subdivided. Following his concept of seniorate, Bolesław divided the country into five principalities: Silesia, Greater Poland, Masovia, Sandomierz and Kraków. The first four provinces were given to his four sons, who became independent rulers. The fifth province, the Seniorate Province of Kraków, was to be added to the senior among the princes who, as the Grand Duke of Kraków, was the representative of the whole of Poland. This principle broke down already within the generation of Bolesław III's sons, when Władysław II the Exile, Bolesław IV the Curly, Mieszko III the Old and Casimir II the Just fought for power and territory in Poland, and in particular over the throne of Kraków. The external borders left by Bolesław III at his death closely resembled the borders left by Mieszko I.