Question: Who is John Corvinus's paternal grandfather?

Knowledge 1: John Corvinus
John Corvinus (Hungarian: "Corvin János", Croatian: "Ivaniš Korvin"; 2 April 1473 – 12 October 1504) was the illegitimate son of Matthias Corvinus, King of Hungary, and his mistress, Barbara Edelpöck. [SEP] Knowledge 2: Matthias Corvinus
Matthias Corvinus, also called Matthias I , was King of Hungary and Croatia from 1458 to 1490.After conducting several military campaigns, he was elected King of Bohemia in 1469 and adopted the title Duke of Austria in 1487.He was the son of John Hunyadi, Regent of Hungary, who died in 1456.In 1457, Matthias was imprisoned along with his older brother, Ladislaus Hunyadi, on the orders of King Ladislaus the Posthumous.Ladislaus Hunyadi was executed, causing a rebellion that forced King Ladislaus to flee Hungary.After the King died unexpectedly, Matthias's uncle Michael Szilágyi persuaded the Estates to unanimously proclaim Matthias king on 24 January 1458.He began his rule under his uncle's guardianship, but he took effective control of government within two weeks.As king, Matthias waged wars against the Czech mercenaries who dominated Upper Hungary (today parts of Slovakia and Northern Hungary) and against Frederick III, Holy Roman Emperor, who claimed Hungary for himself.In this period, the Ottoman Empire conquered Serbia and Bosnia, terminating the zone of buffer states along the southern frontiers of the Kingdom of Hungary.Matthias signed a peace treaty with Frederick III in 1463, acknowledging the Emperor's right to style himself King of Hungary.The Emperor returned the Holy Crown of Hungary with which Matthias was crowned on 29 April 1464.In this year, Matthias invaded the territories that had recently been occupied by the Ottomans and seized fortresses in Bosnia.He soon realized he could expect no substantial aid from the Christian powers and gave up his anti-Ottoman policy.Matthias introduced new taxes and regularly collected extraordinary taxes.These measures caused a rebellion in Transylvania in 1467, but he subdued the rebels.The next year, Matthias declared war on George of Poděbrady, the Hussite King of Bohemia, and conquered Moravia, Silesia, and Lausitz, but he could not occupy Bohemia proper.The Catholic Estates proclaimed him King of Bohemia on 3 May 1469, but the Hussite lords refused to yield to him even after the death of their leader George of Poděbrady in 1471.Instead, they elected Vladislaus Jagiellon, the eldest son of Casimir IV of Poland.A group of Hungarian prelates and lords offered the throne to Vladislaus's younger brother Casimir, but Matthias overcame their rebellion.Having routed the united troops of Casimir IV and Vladislaus at Breslau in Silesia (now Wrocław in Poland) in late 1474, Matthias turned against the Ottomans, who had devastated the eastern parts of Hungary.He sent reinforcements to Stephen the Great, Prince of Moldavia, enabling Stephen to repel a series of Ottoman invasions in the late 1470s.In 1476, Matthias besieged and seized Šabac, an important Ottoman border fort.He concluded a peace treaty with Vladislaus Jagiellon in 1478, confirming the division of the Lands of the Bohemian Crown between them.Matthias waged a war against Emperor Frederick and occupied Lower Austria between 1482 and 1487.Matthias established one of the earliest professional standing armies of medieval Europe (the Black Army of Hungary), reformed the administration of justice, reduced the power of the barons, and promoted the careers of talented individuals chosen for their abilities rather than their social statuses.Matthias patronized art and science; his royal library, the "Bibliotheca Corviniana", was one of the largest collections of books in Europe.With his patronage, Hungary became the first country to embrace the Renaissance from Italy.As Matthias the Just, the monarch who wandered among his subjects in disguise, he remains a popular hero of Hungarian folk tales.
Knowledge 1: John Corvinus
John Corvinus (Hungarian: "Corvin János", Croatian: "Ivaniš Korvin"; 2 April 1473 – 12 October 1504) was the illegitimate son of Matthias Corvinus, King of Hungary, and his mistress, Barbara Edelpöck. [SEP] Knowledge 2: Barbara Edelpöck
Barbara Edelpöck( died 1495) was the mistress of Matthias Corvinus, King of Hungary.She gave birth to the King's only, although illegitimate, child, John Corvinus.
Knowledge 1: John Corvinus
John Corvinus (Hungarian: "Corvin János", Croatian: "Ivaniš Korvin"; 2 April 1473 – 12 October 1504) was the illegitimate son of Matthias Corvinus, King of Hungary, and his mistress, Barbara Edelpöck. [SEP] Knowledge 2: 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.

Answer: John Hunyadi