King Sancho IV of Castile died in the city of Toledo on 25 April 1295, leaving his eldest son Ferdinand as heir of the throne.
After the burial of the sovereign at Toledo Cathedral, his widow María de Molina retired to the Alcázar of Toledo for a mourning of nine days.
The now Dowager Queen was in charge of the regency of her 9-years-old son.
Because the marriage between Sancho IV and María de Molina was without validity, all their children (including the now Ferdinand IV) were illegitimate, so the Dowager Queen had to face numerous problems to keep her son on the throne.

To the incessant struggles with the Castilian nobility, led by the Infante John of Castile, Lord of Valencia de Campos (who claimed the throne of his brother Sancho IV) and by the Infante Henry of Castile the Senator, son of Ferdinand III and great-uncle of Ferdinand IV (who demanded the guardianship of the king) were joined the claims of the Infantes de la Cerda (Alfonso and Ferdinand, sons of the deceased first-born son of Alfonso X, Ferdinand de la Cerda), who were supported by France and Aragon and by their grandmother Dowager Queen Violante of Aragon, widow of Alfonso X. To this were added the problems with Aragon, Portugal and France, who tried to take advantage of the political instability that suffered the Kingdom of Castile in their own benefit.
At the same time, Diego López V de Haro, Lord of Biscay, Nuño González de Lara, and Juan Núñez II de Lara, among many others nobles, sowed confusion and anarchy in the kingdom.

In the Cortes of Valladolid in 1295, Henry of Castile the Senator was appointed guardian of the King, but the Dowager Queen María de Molina got (thanks to the support of the cities with votes in the Cortes) that the custody of her son was entrusted to her.
While celebrating the Cortes of Valladolid, John of Castile, Lord of Valencia de Campos, left the city of Granada and tried to occupy the city of Badajoz, but, when failing in this attempt, he seized Coria and the castle of Alcántara.
He later passed to the Kingdom of Portugal, where he pressed King Denis of Portugal to declare war to Castile and, at the same time, to support his claims to the Castilian throne.

In the summer of 1295, when the Cortes of Valladolid were finished, the Dowager Queen and Henry of Castile met in Ciudad Rodrigo with King Denis of Portugal, to whom they delivered several localities located near the Portuguese border.
In the meeting of Ciudad Rodrigo was renewed the betrothal between Ferdinand IV and Constance of Portugal, daughter of King Denis, and in addition Infanta Beatrice of Castile, younger sister of Fernando IV, would marry Afonso, heir to the Portuguese throne.
At the same time, Diego López V de Haro was confirmed the possession of the Lordship of Biscay, and John of Castile, who recognized (but only privately) Ferdinand IV as his sovereign, was momentarily restored his property.
Shortly after, King James II of Aragon returned the Infanta Isabella of Castile to the Castilian court without having married her, and declared the war to the Kingdom of Castile.

At the beginning of 1296, John of Castile rebelled against Ferdinand IV and took Astudillo, Paredes de Nava and Dueñas, while his son Alfonso of Valencia seized Mansilla.
In April 1296 Alfonso de la Cerda invaded the Kingdom of Castile accompanied by Aragonese troops, and went to the city of León, where John of Castile was proclaimed King of León, Seville and Galicia.
Immediately afterwards, John of Castile accompanied Alfonso de la Cerda to Sahagún, where he was proclaimed King of Castile, Toledo, Córdoba, Murcia and Jaén.
Shortly after being crowned Alfonso de la Cerda and John of Castile, both surrounded the Valladolid municipality of Mayorga, while Henry of Castile parted to the Kingdom of Granada to arrange the peace between the Sultan Muhammed II al-Faqih and Ferdinand IV, since the Granadian troops attacked in those moments in all Andalusia the lands of the King, that were defended, among others, by Alonso Pérez de Guzmán.
On 25 August 1296, the Infante Peter of Aragon died victim of t
King Sancho IV of Castile died in the city of Toledo on 25 April 1295, leaving his eldest son Ferdinand as heir of the throne. After the burial of the sovereign at Toledo Cathedral, his widow María de Molina retired to the Alcázar of Toledo for a mourning of nine days. The now Dowager Queen was in charge of the regency of her 9-years-old son. Because the marriage between Sancho IV and María de Molina was without validity, all their children (including the now Ferdinand IV) were illegitimate, so the Dowager Queen had to face numerous problems to keep her son on the throne.
To the incessant struggles with the Castilian nobility, led by the Infante John of Castile, Lord of Valencia de Campos (who claimed the throne of his brother Sancho IV) and by the Infante Henry of Castile the Senator, son of Ferdinand III and great-uncle of Ferdinand IV (who demanded the guardianship of the king) were joined the claims of the Infantes de la Cerda (Alfonso and Ferdinand, sons of the deceased first-born son of Alfonso X, Ferdinand de la Cerda), who were supported by France and Aragon and by their grandmother Dowager Queen Violante of Aragon, widow of Alfonso X. To this were added the problems with Aragon, Portugal and France, who tried to take advantage of the political instability that suffered the Kingdom of Castile in their own benefit. At the same time, Diego López V de Haro, Lord of Biscay, Nuño González de Lara, and Juan Núñez II de Lara, among many others nobles, sowed confusion and anarchy in the kingdom.
In the Cortes of Valladolid in 1295, Henry of Castile the Senator was appointed guardian of the King, but the Dowager Queen María de Molina got (thanks to the support of the cities with votes in the Cortes) that the custody of her son was entrusted to her. While celebrating the Cortes of Valladolid, John of Castile, Lord of Valencia de Campos, left the city of Granada and tried to occupy the city of Badajoz, but, when failing in this attempt, he seized Coria and the castle of Alcántara. He later passed to the Kingdom of Portugal, where he pressed King Denis of Portugal to declare war to Castile and, at the same time, to support his claims to the Castilian throne.
In the summer of 1295, when the Cortes of Valladolid were finished, the Dowager Queen and Henry of Castile met in Ciudad Rodrigo with King Denis of Portugal, to whom they delivered several localities located near the Portuguese border. In the meeting of Ciudad Rodrigo was renewed the betrothal between Ferdinand IV and Constance of Portugal, daughter of King Denis, and in addition Infanta Beatrice of Castile, younger sister of Fernando IV, would marry Afonso, heir to the Portuguese throne. At the same time, Diego López V de Haro was confirmed the possession of the Lordship of Biscay, and John of Castile, who recognized (but only privately) Ferdinand IV as his sovereign, was momentarily restored his property. Shortly after, King James II of Aragon returned the Infanta Isabella of Castile to the Castilian court without having married her, and declared the war to the Kingdom of Castile.
At the beginning of 1296, John of Castile rebelled against Ferdinand IV and took Astudillo, Paredes de Nava and Dueñas, while his son Alfonso of Valencia seized Mansilla. In April 1296 Alfonso de la Cerda invaded the Kingdom of Castile accompanied by Aragonese troops, and went to the city of León, where John of Castile was proclaimed King of León, Seville and Galicia. Immediately afterwards, John of Castile accompanied Alfonso de la Cerda to Sahagún, where he was proclaimed King of Castile, Toledo, Córdoba, Murcia and Jaén. Shortly after being crowned Alfonso de la Cerda and John of Castile, both surrounded the Valladolid municipality of Mayorga, while Henry of Castile parted to the Kingdom of Granada to arrange the peace between the Sultan Muhammed II al-Faqih and Ferdinand IV, since the Granadian troops attacked in those moments in all Andalusia the lands of the King, that were defended, among others, by Alonso Pérez de Guzmán. On 25 August 1296, the Infante Peter of Aragon died victim of t
Ferdinand IV of Castile