In November 1301, when the court was in the city of Burgos, was made public the bull by which Pope Boniface VIII legitimized the marriage of María de Molina  with the late King Sancho IV, and therefore her children were legitimate from that moment.
At the same time, Ferdinand IV attained his legal majority, who was officially declared on 6 December 1301.
With this, John of Castile and the Infantes de la Cerda lost one of their main arguments when reclaiming the throne, not being able to use the illegitimacy of the Castilian monarch.
In addition was also received the papal dispensation for the marriage of Fernando IV with Constance of Portugal.

Henry of Castile, annoyed by the legitimation of Ferdinand IV by Pope Boniface VIII, allied himself with Juan Núñez II de Lara, in order to indispose and antagonize Ferdinand IV with his mother the Dowager Queen.
Both were joined by John of Castile, who continued to claim the Lordship of Biscay on behalf of his wife, María I Díaz de Haro.

In 1301, while the Dowager Queen was in Vitoria with Henry of Castile answering the complaints presented by the Kingdom of Navarre in relation to the Castilian attacks to their lands, John of Castile and Juan Núñez II de Lara indisposed the King with his mother and sought his amusement in the lands of León by means of hunting, to which Ferdinand IV showed his predilection since childhood.
With the Dowager Queen in Vitoria, the Aragonese nobles revolted against their monarch offered their support to obtain from James II the return to Castile of the towns from which he had taken over in the Kingdom of Murcia.
That same year Henry of Castile, allied with Diego López V de Haro, demanded to Ferdinand IV, in compensation to leave his position of royal guardian (and after having previously blackmailed the Dowager Queen with declaring the war to his son if they didn't accede to his request), the possession of the towns of Atienza and San Esteban de Gormaz, which were granted by the King.

On 23 January 1302 Ferdinand IV married in Valladolid with Constance, daughter of King Denis of Portugal.
In the Cortes de Medina del Campo of May 1302, Henry and John of Castile and Juan Núñez II de Lara tried to indispose the King with his mother, accusing her of having given away the jewels given to her by Sancho IV, and later, when the accusation was proved to be false, they accused her of having appropriated the subsidies granted to the Crown in the Cortes of previous years, an accusation that was also proved false when Nuño, Abbot of Santander and Chancellor of the Dowager Queen, reviewed and made public the accounts of María de Molina, who not only had not appropriated the Crown's funds but contributed with her own income to the support of the monarchy.
While celebrating the Cortes of Medina del Campo in 1302, which was attended by a representation of the King of Castile, Sultan Muhammed II al-Faqih of Granada died and was succeeded by his son, Muhammad III, who attacked the Kingdoms of Castilla y León and conquered the municipality of Bedmar.

In July 1302 Ferdinand IV went to the Cortes de Burgos along with his mother, with whom he had restored good relations, and with Henry of Castile.
The King, although under the influence of his private Samuel de Belorado, of Jewish origin —who tried to indispose the King from his mother— had decided to dispense from the presence of the John of Castile and Juan Núñez II de Lara in the Cortes.
At the end of the Cortes, Ferdinand IV went to the city of Palencia, where was celebrated the marriage of Alfonso of Valencia (son of John of Castile) with Teresa Núñez de Lara (sister of Juan Núñez II de Lara).

At that time was accentuated the rivalry existed between Henry of Castile, María de Molina and Diego López V de Haro on one side, and John of Castile and Juan Núñez II de Lara on the other side.
Henry of Castile threatened the Dowager Queen with declaring the war to Ferdinand IV and herself if his demands were accepted, while the magnates sought to eliminate the influence that María de Molina exerted on her son, of whom the people
In November 1301, when the court was in the city of Burgos, was made public the bull by which Pope Boniface VIII legitimized the marriage of María de Molina  with the late King Sancho IV, and therefore her children were legitimate from that moment. At the same time, Ferdinand IV attained his legal majority, who was officially declared on 6 December 1301. With this, John of Castile and the Infantes de la Cerda lost one of their main arguments when reclaiming the throne, not being able to use the illegitimacy of the Castilian monarch. In addition was also received the papal dispensation for the marriage of Fernando IV with Constance of Portugal.
Henry of Castile, annoyed by the legitimation of Ferdinand IV by Pope Boniface VIII, allied himself with Juan Núñez II de Lara, in order to indispose and antagonize Ferdinand IV with his mother the Dowager Queen. Both were joined by John of Castile, who continued to claim the Lordship of Biscay on behalf of his wife, María I Díaz de Haro.
In 1301, while the Dowager Queen was in Vitoria with Henry of Castile answering the complaints presented by the Kingdom of Navarre in relation to the Castilian attacks to their lands, John of Castile and Juan Núñez II de Lara indisposed the King with his mother and sought his amusement in the lands of León by means of hunting, to which Ferdinand IV showed his predilection since childhood. With the Dowager Queen in Vitoria, the Aragonese nobles revolted against their monarch offered their support to obtain from James II the return to Castile of the towns from which he had taken over in the Kingdom of Murcia. That same year Henry of Castile, allied with Diego López V de Haro, demanded to Ferdinand IV, in compensation to leave his position of royal guardian (and after having previously blackmailed the Dowager Queen with declaring the war to his son if they didn't accede to his request), the possession of the towns of Atienza and San Esteban de Gormaz, which were granted by the King.
On 23 January 1302 Ferdinand IV married in Valladolid with Constance, daughter of King Denis of Portugal. In the Cortes de Medina del Campo of May 1302, Henry and John of Castile and Juan Núñez II de Lara tried to indispose the King with his mother, accusing her of having given away the jewels given to her by Sancho IV, and later, when the accusation was proved to be false, they accused her of having appropriated the subsidies granted to the Crown in the Cortes of previous years, an accusation that was also proved false when Nuño, Abbot of Santander and Chancellor of the Dowager Queen, reviewed and made public the accounts of María de Molina, who not only had not appropriated the Crown's funds but contributed with her own income to the support of the monarchy. While celebrating the Cortes of Medina del Campo in 1302, which was attended by a representation of the King of Castile, Sultan Muhammed II al-Faqih of Granada died and was succeeded by his son, Muhammad III, who attacked the Kingdoms of Castilla y León and conquered the municipality of Bedmar.
In July 1302 Ferdinand IV went to the Cortes de Burgos along with his mother, with whom he had restored good relations, and with Henry of Castile. The King, although under the influence of his private Samuel de Belorado, of Jewish origin —who tried to indispose the King from his mother— had decided to dispense from the presence of the John of Castile and Juan Núñez II de Lara in the Cortes. At the end of the Cortes, Ferdinand IV went to the city of Palencia, where was celebrated the marriage of Alfonso of Valencia (son of John of Castile) with Teresa Núñez de Lara (sister of Juan Núñez II de Lara).
At that time was accentuated the rivalry existed between Henry of Castile, María de Molina and Diego López V de Haro on one side, and John of Castile and Juan Núñez II de Lara on the other side. Henry of Castile threatened the Dowager Queen with declaring the war to Ferdinand IV and herself if his demands were accepted, while the magnates sought to eliminate the influence that María de Molina exerted on her son, of whom the people 
Ferdinand IV of Castile