time, he also made an alliance with Duke Władysław of Opole, who promised to help Henry IV with the condition that his daughter (perhaps called Constance), who had recently married Henry IV, was crowned with him as Polish queen if he would obtain the royal investiture. Attempts to obtain supreme authority over Silesia and all Poland The relation of Henry IV with his Silesian relatives, in general, was not good. In 1280 he again suffered the invasion of the Duke Henry V the Fat of Legnica, who was supported by the Margrave of Brandenburg, who could resist with unusual difficulty. In order to normalize the situation in February of the next year Henry IV organized a meeting in Sądowel, a village located in the Duchy of Wrocław, for the purpose to find ways of mutual cooperation between the Silesian dukes. Henry IV, however, had other plans: immediately he captured his long-time enemy, Duke Henry V the Fat of Legnica, as well as his own allies, Dukes Henry III of Głogów and Przemysł II of Greater Poland, in order to obtain political concessions from them. Przemysł II was forced to give the strategic Lesser Polish land of Wieluń (also known as Ruda) and to acknowledge Henry IV's overlordship, paying homage to him. In subsequent years, the good politics of Henry IV were reflected in the voluntary submission of the Silesian dukes Przemko of Ścinawa and Bolko I of Opole; the re-unification of Silesia seemed within reach. However, not all the Silesian dukes accepted his authority: Dukes Bolko I the Strict, Konrad II the Hunchback and three of the four sons of Władysław of Opole: Casimir of Bytom, Mieszko I of Cieszyn and Przemysław of Racibórz were completely against Henry's politics. With the Opole Dukes, the situation was more delicate: in 1287, Henry IV obtained the annulment of his marriage with their sister, who was sent back to her homeland. The fourth of Władysław's sons, Bolko I, remained faithful to Henry IV's politics. The first attempt of Henry IV to take the Seniorate Province at Kraków was during 1280–1281, as a response to the invasion which the Polish High Duke Leszek II the Black had made against Wrocław before. However, this trip ended unsuccessfully. Conflict with Bishop Thomas II of Wrocław In the years 1282–1287 Henry IV was involved in a long-lasting dispute with the Bishop of Wrocław Tomas II Zaremba. The