This story about Vargas is from '
Don Quixote':
"I remember having read," [DQ] added, "how a Spanish knight,
Diego Pérez de Vargas by name, having broken his sword in battle, tore from an oak a ponderous bough or branch. With it he did such things that day, and pounded so many Moors, that he got the surname of Machuca and his descendants from that day forth are called Vargas y Machuca."