In the year 1035, when king Sancho el Mayor of Navarre – who had coined a currency with the title of “Emperor of Spains” (Emperador de las Españas) died – his extensive territories were divided among the heirs. One of them was the firstborn, García Sánchez III of Navarre, known as “the Najeran” because that was his capital. The second son, Fernando, received the earldom of Castilla. At the beginning of his reigns, Garcia helped his brother resist the king’s Bermuda III of León attacks – he was brother of Fernando’s wife. That led to the death of Bermuda in the Battle of Tamarón. Following his death, Fernando’s wife inherited the kingdom, and he became the only monarch. From that moment on, the second son went on to overcome the firstborn in territories and power. That gave rise to the Battle of Atapuerca.
On September 1, 1054, both kings met with their respective armies, face to face, in the southern plain of Sierra de Atapuerca. The confrontation between brothers began some years before, when Fernando traveled to Nájera to visit his sick brother and he treated him in a vexatious way. When, repentant, Garcia returned the visit in order to restore the relationship, Fernando denied. After managing to escape and return to Navarre, García summoned the third brother –Ramiro I of Aragón, who was his vassal- to attack Fernando together. The attempts of the chaplain of the Navarrese king – Íñigo, Abbot of Oña and future Saint- to reconcile them, were vain.
In the course of the Battle of Atapuerca, King García Sánchez III was killed “in a wicked way” by some Leonese knights, relatives of the deceased King Bermudo. According to the chronicle of Nájera, the Leonese knights had disobeyed the order of their king of not to fight directly with Garcia in order to force his surrender. Garcia died in the arms of his chaplain, in a place known as Prado Redondo, southwest of the town of Agés. King Ferdinand sent a huge stone to the site to be marked. The battle came to an end because of the death of the king of Pamplona. Then, the noble vassals of García met in the same field of the Battle of Atapuerca with his heir of only 14 years. He was proclaimed King of Navarre with the name of Sancho Garcés IV. The Navarrese nobles veiled the corpse there, moving it in procession to the cemetery of the great basilica of Santa María la Real de Nájera, built by him.
Because of the war, the very young king of Navarre lost the border territories with Castile, as well as the nobles of that area. In the following decades the king managed to balance his relationship with his uncle Fernando and his successors, his cousin Sancho II “El fuerte” and the brother of the latter – and also with his first cousin – Alfonso VI. What Garcia did not get is to put an end to the intrigues of his seven brothers, related to numerous magnates. On the other hand, his decision not to attack the Taifa kingdom of Zaragoza in exchange for a succulent annual payment resulted a great wealth. However, this made him greedy for power and gave him time and the reason to participate in conspiracies.
In 1076, when the king was hunting in the high plateau that dominates the town of Funes, Sancho Garcés IV was pushed to the ravine of Peñalén by his brothers Ramón and Ermesinda. Relying on the support of the magnates who were his accomplices, the fratricide Ramón went to Pamplona in order to be proclaimed king; but he did not get it. Also, the attempt to crown the deceased’s eldest son went in vain. His cousin Sáncho V Ramírez -rey of Aragón- was chosen by the Navarrese nobility, while the other cousin -Alfonso VI of Castilla y León- got control over Riojan and Basque territories.