DukeWilliam of Opava (Czech:Vilém Opavský;c. 1410 – 15 August 1452) was a member of Opava branch of the BohemianPřemyslid dynasty. He was Duke ofOpava from 1433 to 1452 and Duke ofMünsterberg from 1443 to 1452.

His parents werePrzemko I, Duke of Opava (d. 1433) and his second wife, Catherine of Münsterberg (d. 1422).

His father died in 1433, leaving five sons. The oldest brother,Wenceslaus II took up the guardianship for his younger half-brothers William,Ernest andPrzemko II, while Wenceslaus's younger brotherNicholas IV styled himself Lord ofZlaté Hory. Although their father had stipulated in his will that they should rule the duchy jointly, the brothers divided their inheritance around 1435. William and Ernest received shares of Opava; theDuchy of Głubczyce was split off for Wenceslas.^[1] The youngest brother, Przemko II, was destined for an ecclesiastical career and did not receive a share of the duchy. The duchy was now so fragmented that the revenue did not cover the Duke's cost of living. William saw no option but to become arobber baron.

Hynek Krušina of Lichtenburg acquired theDuchy of Münsterberg in 1440. The Estates, however, rejected him as their sovereign. After length negotiations, they elected William of Opava as their new Duke. William's claim to Münsterberg was based on two relationships: his mother had been the sister ofJohn I, the last Duke of Münsterberg from thePiast dynasty, and he was married to Salome, a daughter ofPůta III of Častolovice, who had been the lawful pledge lord of Münsterberg until he died in 1434. William accepted his election and changed from a robber baron into a defender of the peace. Together with DukesNicholas V (d. 1452) of Krnov,Przemyslaus II of Cieszyn andHenry IX ofŻagań-Głogów he fought as captain ofWrocław against highway robbers and robber barons.

In 1443, he formed an alliance with ArchbishopConrad of Wrocław and the Dukes of Wrocław,Jawor andLegnica againstHynek Krušina of Lichtenburg. Although Hynek had never given up his claims on Münsterberg, the dispute was resolved in 1444 and the Duchy of Münsterberg was granted to William, except the district ofZąbkowice Śląskie. The citizens of that district had fought on Hynek's side during the conflict and Hynek was allowed to retain the district.

In 1451, William transferred his ownership of Münsterberg to his brother Ernest, in exchange for a 1/3 share in the ownership of theDuchy of Opava. Since William had received another 1/3 share when his father's inheritance had been divided in 1435, he now owned 2/3 of Opava.^[2]

William died in 1452. His brother Ernest took up the guardianship of William's children. As their guardian, he sold William's 2/3 share of Opava to DukeBolko V ofOpole, in or after 1454. On 8 March 1456, Ernest sold the Duchy of Münsterberg toGeorge of Poděbrady, who would be elected King of Bohemia in 1458. George purchased the 1/3 share of Opava after Bolko's death from the latter's brotherNicholas I and in 1464, he purchased the other 2/3 in Opole in 1464 fromJohn II, thereby considerable increasing his political and economic influence inSilesia.

William of Troppau died in 1452. He was buried in the Holy Spirit Church inOpava.

William was married with Salome, a daughter of the East Bohemian noblemanPůta III of Častolovice and his wife, Anna, the daughter ofAlbert of Koldice. They had the following children:

• Frederick (d. 1470)
• Wenceslas III (d. 1474)
• Przemko III (d. 1493)
• Catherine (1443–1505), married toJohn II, Duke of Żagań
• Anna (d. 1515),abbess of theSanctuary of St. Jadwiga in Trzebnica

• Ludwig Petryet al.:Geschichte Schlesiens, vol. 1, Sigmaringen, 1988,ISBN 3-7995-6341-5, pp. 191, 201, 205, 208, 212
• Hugo Weczerka (ed.):Handbuch der historischen Stätten — Schlesien. Stuttgart, 1977,ISBN 3-520-31601-3, p. 218

• Marek, Miroslav."Genealogy of Opava". Genealogy.EU.