Sancho of Aragon (archbishop of Toledo)
Sancho of Aragon (1250 – Martos, 1275) was an Infante of Aragon and Archbishop of Toledo, who was killed by the Moors.
Joanna of Aragon, Countess of Ampurias
Joanna of Aragon( Barcelona 7 November 1344- Castellón, Ampurias 1385) was the second child of Peter IV of Aragon and his first wife Maria of Navarre.
She was an Infanta of Aragon by birth and Countess of Ampurias by her marriage.
She was a member of the House of Aragon.
Eleanor of Aragon, Queen of Castile
Eleanor of Aragon (20 February 1358 – 13 August 1382) was a daughter of King Peter IV of Aragon and his wife Eleanor of Sicily.
She was a member of the House of Aragon and Queen of Castile by her marriage.
Eleanor of Aragon, Countess of Toulouse
Eleanor of Aragon, Countess of Tolouse( 1182–1226) was a daughter of King Alfonso II of Aragon and Sancha of Castile, Queen of Aragon.
She married Raymond VI, Count of Toulouse.
Felicia of Roucy
Felicia of Roucy( – 3 May 1123) was a queen consort of Aragon and Navarre.
She was a daughter of Hilduin IV of Montdidier and his wife Alice of Roucy.
She was married in 1076 to Sancho Ramírez, then king of Aragon after he had divorced his first wife, Isabella of Urgell.
His accession to the crown of Navarre later that year made her the first Aragonese consort to also be Queen consort of Navarre.
She is attested shortly before her husband's death and is now thought to have outlived Sancho( the supposed subsequent marriage of Sancho to a third wife, Philippa of Toulouse, appearing in a later chronicle, is now thought to be erroneous).
Felicia gave birth to three sons, Ferdinand, Alfonso and Ramiro, the latter two following her step- son Peter I of Aragon and Navarre in Aragon( Alfonso also in Navarre).
Through Ramiro's only daughter Petronila of Aragon, she was ancestor of the later rulers of Aragon.
Isabella of Aragon, Countess of Urgell
Isabella of Aragon( 1376, Barcelona – 1424) was a daughter of Peter IV of Aragon and his fourth wife, Sibila of Fortia.
She was infanta of Aragon and Countess of Urgel.
Bertha of Aragon
Bertha of Aragon( c. 1075 – bef. 1111) was a Queen consort of Aragon and Navarre.
Nothing is known about her childhood or the names of her parents, it is believed that she is Italian since her name was" Berta", which is Italian.
She was married to Peter I of Aragon in 1097, shortly after the death of Peter's first wife, Agnes of Aquitaine, with whom he had two children: Peter and Isabella.
Bertha and Peter had no children.
Peter and Isabella were both dead by 1104 and King Peter needed an heir.
They had no children and Peter died the following year.
The crown of Aragon and Navarre passed to Alfonso who was the half brother of Peter.
Bertha got a dower but Alfonso got all of Peter's lands.
It is unknown when Bertha died or where she died.
Genealogist Szabolcs de Vajay has speculated that Bertha may have been a daughter of Peter I, Count of Savoy, and another Agnes of Aquitaine, perhaps the Agnes who was the final wife of Peter's father Ramiro I of Aragon and first- cousin of Peter's own first wife.
Peter I of Aragon and Pamplona
Peter I (1068 - 1104) was King of Aragon and also Pamplona from 1094 until his death in 1104.
Peter was the eldest son of Sancho Ramírez, from whom he inherited the crowns of Aragon and Pamplona, and Isabella of Urgell.
He was named in honour of Saint Peter, because of his father's special devotion to the Holy See, to which he had made his kingdom a vassal.
Peter continued his father's close alliance with the Church and pursued his military thrust south against bordering Al-Andalus taifas with great success, allying with Rodrigo Díaz de Vivar, known as "El Cid", the ruler of Valencia, against the Almoravids.
According to the medieval "Annales Compostellani" Peter was "expert in war and daring in initiative", and one modern historian has remarked that "his grasp of the possibilities inherent in the age seems to have been faultless."
Isabella of Aragon, Queen of Germany
Isabella of Aragon( 1305 – 12 July 1330) was the daughter of James II of Aragon and his second wife Blanche of Anjou.
Queen consort of Frederick I of Austria.
She was a member of the House of Aragon
Agnes of Aquitaine, Queen of Aragon and Navarre
Agnes of Aquitaine (end of 1072 – 6 June 1097) was a daughter of William VIII, Duke of Aquitaine, and his third wife, Hildegarde of Burgundy, and thus half-sister of Agnes of Aquitaine, Queen of Castile, with whom she is sometimes confused.
In 1081, Agnes was betrothed to Peter I of Aragon and Navarre.
During 1086 in Jaca the couple married, and upon Peter's succession, Agnes became queen of Aragon and Navarre.
By him, Agnes had two children, both of whom predeceased their father: Peter (died 1103) and Isabella (died 1104).
Agnes died in 1097, and her husband remarried to a woman named Bertha.

Question: Who is the mother-in-law of Agnes Of Aquitaine, Queen Of Aragon And Navarre?
Answer: Isabella of Urgell