Page "Sancho IV of Castile" Paragraph 2

Sancho was recognised and supported by the majority of the nobility and the cities, but a sizable minority opposed him throughout his reign and worked for the heirs of Ferdinand de la Cerda.

One of the leaders of the opposition was his brother John, who united to his cause the lord of Biscay, Lope Díaz III de Haro.

Sancho responded by executing the Lord of Biscay and incarcerating his brother.

According to the chroniclers, he cemented his hold on power by executing 4, 000 other followers of Infante Alfonso, son of Ferdinand de la Cerda, in Badajoz.

He executed 400 more in Talavera and more in Ávila and Toledo.