This illustration from a fourteenth centry French manuscript depicts
the beheading of Pedro of Castile. The image appears in the Grandes
Chroniques de France
(Bib. Nat. Fr., FR 2813 fol. 447).
fought alongside Pedro at
the Battle of Najera
, and Pedro's daughter
Constance married John of Gaunt
If you are so inclined, you can also take a look at the banner
(bearing the Castilian coat of arms
) that Pedro used.