The Second Battle of Olmedo was a pivotal confrontation occurring amid the broader succession crisis facing the Kingdom of Castile in the late 15th century. At the heart of this conflict was King Henry IV of Castile, whose reign was plagued by controversy and disputes surrounding his legitimacy, particularly concerning his daughters' legitimacy and his marital ties. Opposing him was his half-brother, Alfonso, Prince of Asturias, who was supported by a faction of the nobility dissatisfied with Henry's rule. The battle took place in the vicinity of Olmedo, a strategic location that had already witnessed military actions in service of claims to the throne.

On the morning of the battle, troops loyal to Alfonso, spearheaded by powerful noble families, mobilized against Henry IV's forces. The encounter was fierce and marked by shifting allegiances, as many nobles were torn between loyalty to the king and the promise of a strong claim represented by Alfonso. Ultimately, the forces supporting Alfonso emerged victorious, which bolstered his position and further exacerbated the split in Castilian politics. The victory at Olmedo underscored the complex dynamics of power, influence, and loyalty within the kingdom at this time.

Following the battle, Alfonso's increased prominence posed continuing challenges for Henry IV, who struggled to maintain control and legitimacy as king. The battle's aftermath would set the stage for further confrontations within the court and foreshadow the future consolidation of power that would eventually come with the rise of Isabella of Castile, Henry's half-sister. The interpersonal and political fractures revealed by the conflict at Olmedo contributed to the evolving narrative of Castilian governance, influencing the trajectory of the Spanish throne in the subsequent decades.