Kingdom of England unity ever since. During the reign of Æthelred the Unready (978–1016), a new wave of Danish invasions was orchestrated by Sweyn I of Denmark, culminating after a quarter-century of warfare in the Danish conquest of England in 1013. But Sweyn died on 2 February 1014, and Æthelred was restored to the throne. In 1015, Sweyn's son Cnut the Great (commonly known as Canute) launched a new invasion. The ensuing war ended with an agreement in 1016 between Canute and Æthelred's successor, Edmund Ironside, to divide England between them, but Edmund's death on 30 November of that year left England united
Alfonso Enríquez, Count of Gijón and Noreña of the stipulations of the treaty was the marriage of Alfonso Enríquez with Isabel of Portugal, a natural daughter of King Ferdinand I, who at that time was about nine years old. Alfonso's father, King Henry II, died in May 1379 and was succeeded by his first-born son who reigned as John I of Castile. In the spring of 1381, King John I was preparing to go to war with Portugal. His half-brother, Alfonso Enríquez, knowing that all the soldiers from Asturias were away from the region, offered England, an ally of Portugal, the harbor of Gijón. Upon hearing this,