Jan I of Żagań
Jan I of Żagań  (– 12 April 1439) was a Duke of Żagań-Głogów, since 1397 (until 1412 with his brothers as co-rulers), since 1403 Duke of Żagań, Krosno Odrzańskie and Świebodzin (again, until 1412 with his brothers as co-rulers) and since 1412 sole ruler of Żagań and Przewóz.
He was the eldest son of Henry VIII the Sparrow, Duke of Głogów by his wife Katharina, daughter of Duke Władysław of Opole.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Henry VIII the Sparrow
Henry VIII (VI)
the Sparrow
(– 14 March 1397) was a Duke of Żagań–Głogów during 1368–1378 (as a co-ruler with his brothers), from 1378 ruler over Zielona Góra, Szprotawa, Kożuchów, Przemków and Sulechów, and since 1395 ruler over half of Głogów, Ścinawa and Bytom Odrzański.
He was the second son of Henry V of Iron, Duke of Żagań–Głogów, by his wife Anna, daughter of Duke Wenceslaus of Płock.
The origin of his nickname "SparrowWróbel") is unknown.
Wenceslaus of Żagań
Wenceslaus of Żagań( ca. 1434 – 29 April 1488) was a Duke of Żagań- Przewóz since 1439( with his brothers as co-rulers until 1449), from 1449 Duke of Przewóz( as co-ruler of his younger brother).
He was the third son of Duke Jan I of Żagań by his wife Scholastika, daughter of Rudolf III, Duke of Saxe- Wittemberg and Elector of Saxony.
His uncle, Joe II of Żagań, was his guiding mentor through childhood.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Johan Braakensiek
Johan Coenraad Braakensiek( 24 May 1858, Amsterdam – 27 February 1940, Amsterdam) was a Dutch painter, illustrator and political cartoonist.
He is the grandfather of Jan van Oort.
Rudolf of Żagań
Rudolf of Żagań( ca. 1418 – 18 September 1454) was a Duke of Żagań- Przewóz since 1439( with his brothers as co-rulers until 1449), from 1449 Duke of Żagań( as co-ruler of his older brother).
He was the second son of Duke Jan I of Żagań by his wife Scholastika, daughter of Rudolf III, Duke of Saxe- Wittemberg and Elector of Saxony.
He was named after his maternal grandfather.
Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Jan II the Mad
Jan II the Mad also known as the Bad, the Wild or the Cruel( 16 April 1435 – 22 September 1504), was a Duke of Żagań- Przewóz since 1439( with his brothers as co-rulers until 1449), from 1449 Duke of Przewóz( as co-ruler of his younger brother), during 1461 – 1468 and briefly in 1472 Duke of Żagań and during 1476 – 1488 Duke of half- Głogów( the Duchy was finally reunited in 1480).
He was the fourth and youngest son of Duke Jan I of Żagań by his wife Scholastika, daughter of Rudolf III, Duke of Saxe- Wittenberg and Elector of Saxony.
Balthasar of Żagań
Balthasar, Duke of Żagań( – Przewóz, 15 July 1472), was a Duke of Żagań- Przewóz since 1439( with his brothers as co-rulers until 1449), from 1449 Duke of Żagań.
Deposed during 1461 – 1468, he recovered the Duchy in this year until shortly before his death.
He was the oldest son of Duke Jan I of Żagań by his wife Scholastika, daughter of Rudolf III, Duke of Saxe- Wittemberg and Elector of Saxony.
He was named after his maternal great- grandfather, Balthasar, Landgrave of Thuringia( Scholastika's maternal grandfather).

Question: Who is the paternal grandfather of Jan I Of Żagań?