Guglielmo d'Aragona, conte di Malta e Gozo

King Federigo II had one illegitimate son by Mistress (1):

-http://fmg.ac/Projects/MedLands/SICILY.htm#Mariadied1401
b) GUILLERMO d'Aragona (-after 1380). Zurita records the death in Messina 27 Jul 1377 of “el Rey don Fadrique”, leaving “la Infanta doña Maria su hija” as his universal heir “en el Reyno de Sicilia y en los Ducados de Athenas y Neopatria...y en las islas adjacentes” except for “las islas de Malta y del Gozo” which he bequeathed to “don Guillen de Aragon hijo suyo natural”[774]. Conte di Gozo e Malta.

m as her first husband, BEATRIZ de Aragón-Avola, daughter of JUAN de Aragón Barone di Avola & his wife Giovanna ---.

Guillermo & his wife had one child: 

• i) GIOVANNA d’Aragona. m PIETRO di Gioeni, Barone di Ardore, son of ---.

  ---

-https://gw.geneanet.org/jpbuhagiar?lang=en&pz=jean+pierre+baptiste+...

/// Wikipedia : « He is the illegitimate son of King Frederick III of Sicily and an unknown mistress [1].

 Malta had been attributed in 1366 to Manfredi III Chiaromonte.  But this appointment had been badly accepted by the strong man of the island, Giacomo de Pellegrino, both captain of the garrison and privateer.  The revolt lasted several years until it was put down by a fleet of Genoese galleys and by the visit to the island of Frederick III in person.  The king then decides to have the island administered by Jean Frédéric d'Aragon, asking him to stay and live there in order to calm the revolt durably [2].

 When the king died in 1377, the county of Malta returned by will to Guillermo [3].  But it seems that this appointment was virtual, Malta being attributed by King Peter IV of Aragon to Louis Frederick of Aragon [2].  In reality, it is likely that Malta continued to be administered by Manfredi III Chiaromonte, became the vicar and principal ruler of Sicily.

 He was married to Beatrice d'Aragón-Avola [4] (daughter of Giovanna and Juan de Aragón, Baron d'Avola, and granddaughter of Orlando of Aragon) from whom he had at least one daughter, Giovanna, who married Pietro  di Gioeni, Baron d'Ardore [4].

 Another daughter is sometimes attributed to him, Margarita d'Aragon, who married Giacomo de Pellegrino [5].  but it is more likely that Margarita was the illegitimate daughter of William II of Athens, son of Frederick II of Sicily (6). »