In the (vain) hope to prevent an inheritance dispute, the
Piast prince
Bolesław III Wrymouth by his last will and
testament had divided
Poland into hereditary provinces distributed among his four sons:
Masovia,
Kujawy,
Greater Poland and Silesia. Beside which, the
Seniorate Province (
Lesser Poland) with the residence of
Kraków was reserved for the eldest, who according to the principle of
agnatic seniority was to be
High Duke of all Poland. This act inadvertently started the process known as
Fragmentation of Poland. Bolesław's son
Władysław II received the Duchy of Silesia and, as the eldest, was also granted the title of a High Duke among with the Seniorate Province. Nevertheless, after he had tried to gain control over all Poland, he was banned and expelled by his younger half-brothers in 1146. Bolesław's second eldest son
Bolesław IV the Curly, Duke of Masovia, became Polish High Duke. When, in 1163, Władysław's three sons, backed by Emperor
Frederick I Barbarossa returned to Poland, Bolesław IV had to restore their heritage. After ten years of joint rule, Władysław's sons finally divided Silesia in 1173: •
Bolesław I the Tall, the eldest, received the core territory around the residences of
Wrocław,
Legnica and
Opole. In 1180, he granted the
Duchy of Opole to his son
Jarosław, who ruled until his death in March 1201. Upon Bolesław's death in December 1201, his lands were inherited by his only remaining son
Henry I the Bearded. •
Mieszko I Tanglefoot became Duke of
Racibórz and received
Bytom and
Oświęcim in 1177. •
Konrad Spindleshanks (
Konrad Laskonogi), the youngest, in 1177 also claimed his rights and received the
Duchy of Głogów from his brother Bolesław, who after Konrad's death about 1180/90 again inherited it. File:Silesia 1172-1177.jpg|1172/3-1177 File:Silesia 1177-1185.jpg|1177-1185 File:Silesia 1185-1201.jpg|1185-1201 File:Silesia 1201-1202.jpg|1201-1202 After his brother Bolesław I had died, Mieszko I Tanglefoot also conquered and took the Duchy of Opole from his nephew Henry I the Bearded. He ruled over the Racibórz and Opole duchies, which emerged as
Upper Silesia, until his death in 1211. Henry I the Bearded remained sovereign of the
Lower Silesian Duchy of Wrocław, he acquired the Greater Polish lands of
Kalisz in 1206, which he granted to his Piast cousin
Władysław Odonic, as well as
Lubusz Land in 1210. High Duke of Poland from 1232, he conquered further Greater Polish territories around
Santok in 1234. Mieszko's heir was Duke
Casimir I of Opole, who died in 1230. Thereupon, Henry I managed to reunite whole Silesia under his reign. He was succeeded by his son
Henry II the Pious in 1238, while Upper Silesia was inherited by Casimir's son
Mieszko II the Fat in 1239. He and his younger brother,
Władysław Opolski, had already received Greater Polish Kalisz in 1234. Henry II was killed at the
Battle of Legnica in 1241. His eldest son and heir, Duke
Bolesław II the Bald temporarily gave Lubusz Land to his younger brother
Mieszko († 1242). He reconciled with his Greater Polish cousin Duke
Przemysł I and finally returned Santok in 1247 and remained sole ruler of Lower Silesia until 1248. Mieszko II the Fat, of Upper Silesia, in 1244, returned Kalisz to Duke
Przemysł I of Greater Poland. He died in 1246 and his possessions were inherited by his brother Władysław Opolski. File:Silesia 1206-1217.jpg|1206-1217 File:Silesia 1217-1230.jpg|1217-1230 File:Silesia 1241-1243.jpg|1241-1243 File:Silesia 1243-1248.jpg|1243-1248 ==Duchies of the Bohemian Crown (1335–1918)==