John I of Castile
In April 1385, John of Aviz was recognized as king by the Cortes. This triggered an invasion of the country by King John I of Castile, in support of his wife's rights to the throne. Nuno Álvares Pereira was engaged against the northern cities loyal to the Castilians. During this time of war, he fed the hungry populations of his Castilian opposition at his own expense.