the last will and testament of the piast duke bolesław iii wrymouth of poland, established rules for governance of the polish kingdom by his four surviving sons after his death. by issuing it, bolesław planned to guarantee that his heirs would not fight among themselves, and would preserve the unity of his lands under the piast dynasty. however, he failed; soon after his death his sons fought each other, and poland entered a period of fragmentation lasting about 200 years.