Peter IV. von Aragon was son of Alfons IV. von Aragon, one son of Johann II. von Aragon.

Johann II. von Aragon was son of Peter III. von Aragon and Constanze von Hohenstaufen, daughter of Manfred von Hohenstaufen and Beatrix von Savoy.

Beatrix von Savoy was daughter of Amadeus IV. von Savoy.

Peter IV. von Aragon was married to Leonora, daughter of Peter II. von Sizilien and Elisabeth von Kaernten. See Otto II. von Kaernten.

His daughter also, Leonora, married Johann I. von Castil, followed by:

Ferdinand I. von Aragon
Alphonse V. von Aragon and his son:
Ferdinand I. von Neapel

Leonora von Neapel married Ercole I. von Este, followed by:
Alphonse I. von Este

Ercole II.von Este married to Renee von Milan, daughter of Ludwig XII., Koenig von Frankreich.

Renee's daughter, Anna von Este, married Jacob I. von Nemours Savoy.