Bolesław III Wrymouth in the context of "Dukes of Masovia"

Poland was ruled at various times either by dukes and princes (10th to 14th centuries) or by kings (11th to 18th centuries). During the latter period, a tradition of free election of monarchs made it a uniquely electable position in Europe (16th to 18th centuries).

The first Polish ruler whose existence is not debatable was Duke Mieszko I, who adopted Christianity under the authority of Rome in the year 966. He was succeeded by his son, Bolesław I the Brave, who greatly expanded the boundaries of the Polish state and ruled as the first king in 1025. The following centuries gave rise to the mighty Piast dynasty, consisting of both kings such as Mieszko II Lambert, Przemysł II or Władysław I the Elbow-high and dukes like Bolesław III Wrymouth. The dynasty's rule over Poland ceased with the death of Casimir III the Great in 1370. In the same year, the Capetian House of Anjou became the ruling house with Louis I as king of both Poland and Hungary. His daughter, Jadwiga, later married Jogaila, the pagan Grand Duke of Lithuania, who in 1386 was baptized and crowned as Władysław II Jagiełło, thus creating the Jagiellonian dynasty and a personal union between Poland and Lithuania.

Opole (Polish: [ɔˈpɔlɛ] ; German: Oppeln; Silesian: Ôpole; Silesian German: Uppeln) is a city located in southern Poland on the Oder River and the historical capital of Upper Silesia. With a population of approximately 127,387 as of the 2021 census, it is the capital of Opole Voivodeship (province) and the seat of Opole County. Its metropolitan area was home to 146,522 inhabitants. It is the largest city in its province.

Its history dates to the 8th century, and Opole is one of the oldest cities in Poland. An important stronghold in Poland, it became a capital of a duchy within medieval Poland in 1172, and in 1217 it was granted city rights by Duke Casimir I of Opole, the great-grandson of Polish Duke Bolesław III Wrymouth. During the Medieval Period and the Renaissance, the city was known as a centre of commerce; several main trade routes intersected here, which helped to generate steady profits from transit trade. The rapid development of the town was also caused by the establishment of a seat of regency in Opole in 1816. The first railway connection between Opole, Brzeg and Wrocław was opened in 1843 and the first manufacturing plants were constructed in 1859, which greatly contributed to the city's regional significance.

The Silesian Piasts were the elder of four lines of the Polish Piast dynasty beginning with Władysław II the Exile (1105–1159), eldest son of Duke Bolesław III of Poland. By Bolesław's testament, Władysław was granted Silesia as his hereditary province and also the Lesser Polish Seniorate Province at Kraków according to the principle of agnatic seniority.

Mieszko III (c. 1122/25 – 13 March 1202), sometimes called Mieszko the Old, was Duke of Greater Poland from 1138 and High Duke of Poland, with interruptions, from 1173 until his death.

He was the fourth and second surviving son of Duke Bolesław III Wrymouth of Poland, by his second wife Salomea, daughter of the German count Henry of Berg-Schelklingen.

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, soon after his death his sons fought each other, and Poland entered a period of fragmentation lasting about 200 years.