( El Prudente )Earned for his meticulous and guarded political management, through which he maintained the integrity of the vast empire he inherited.
( El César )A nod to his immense power as the ruler of both the Spanish Empire and the Sacro Imperio Romano Germánico .
( El Hermoso )A straightforward tribute to his physical attractiveness —he was described as a tall man with a well-formed body and beautiful eyes.
( La Loca )Named for a supposed mental illness that her father and son used as a justification to keep her confined and away from the throne.
