Ernest, Duke of Opava
Ernest of Opava( – 1464) was a member of the Opava branch of the Přemyslid dynasty.
He was Duke of Opava from 1433 to 1461 and Duke of Münsterberg from 1452 to 1456.
Przemko II, Duke of Opava
Przemko II of Opava(( – 16 June 1478) was a member of the Opava branch of the Přemyslid dynasty.
He was Duke of Opava from 1433 until his death.
From 1466, he was also a member of the cathedral chapter of Wrocław.
In older literature, he is sometimes confused with his nephew Przemko III.
Nicholas IV, Duke of Opava
Duke Nicholas IV of Opava( – 1437) was Duke of Opava and Lord of Zlaté Hory from 1433 until his death.
Wenceslaus I, Duke of Opava
Wenceslaus I of Opava( – 1381) was a member of the Opava branch of the Přemyslid dynasty.
He was Duke of Opava from 1367 until his death.
Nicholas III, Duke of Opava
Nicholas III of Opava( – 9 July 1394) was Duke of Opava from 1367 to 1377 and Duke of Głubczyce from 1377 until his death.
Anna of Racibórz
Anna of Racibórz (b. 1292/98 – d. 1 January/21 August 1340), was a Polish princess member of the House of Piast in the Racibórz branch and by marriage Duchess of Opawa and Racibórz.
She was the second child but eldest daughter of Duke Przemysław of Racibórz by his wife Anna, daughter of Duke Konrad II of Masovia.
Přemek I, Duke of Opava
Přemek I, Duke of Opava'( or Przemko I)( born:; died: 28 September 1433) was a member of the Opava branch of the Bohemian Přemyslid dynasty.
He was Duke of Opava from 1367 until his death and Głubczyce from 1394 until his death.
Frederick, Duke of Opava
Frederick, Duke of Opava( – 1470) was a member of the Opava branch of the Bohemian Přemyslid dynasty.
He was co-ruler of Opava from 1452 to 1456.
William, Duke of Opava
Duke William of Opava( – 15 August 1452) was a member of Opava branch of the Bohemian Přemyslid dynasty.
He was Duke of Opava from 1433 to 1452 and Duke of Münsterberg from 1443 to 1452.
Margaret of Opava
Margaret of Opava
(Czech: "Markéta Opavská", Silesian: "Margaret s Uopawje", German: "Margaret von Troppau", Polish: "Małgorzata opawska"; 1330–1363) was the youngest daughter of Nicholas II of Opava, (grandson of Přemysl II, Otakar, King of Bohemia) and his third wife Anna of Racibórz.
She became Margravine consort of Moravia by her marriage to John Henry of Moravia (1353).
Margaret was buried in Saint Thomas, Brno.

Question: Who is the maternal grandfather of Margaret Of Opava?
Answer: Przemysław of Racibórz