I am surprised to find the internet has several images of Maria de Padilla.
Her daughters married John of Gaunt and Edmund of Langley and she was the grandmother of Catherine of Lancaster, aka Catalina, Queen of Castile, Edward, Duke of York, Constance of York and Richard of Conisbrough. (Richard of Conisbrough is known thus to historians but as Lord Richard of York in his lifetime, later Earl of Cambridge. But that’s a detail.)
What is really cool about Maria is that her coat of arms included frying pans. This may be unique in heraldry, it is certainly unusual. It is apparently a pun on her surname, which I presume works in Castilian. Not three lions on a shirt – four frying pans on a shield. (Or in her case, a lozenge.)
Apparently Donizetti wrote an opera about her.
The unusual coat of arms may be seen attached to her Wiki article.