You might have heard "El día de reyes" wich is short for "El día de los reyes magos" wich can translate to : the day of the three wise men . This is celebrated in Spain on January 6th (also called " Epifanía del señor"/Epiphany of the lord) The bible tells the story that when Jesus was born , three wise men arrived and gifted the child . In Spain this day is very important, even more than Christmas, the family gahters for diner on January 5th and the children get presents the next morning. You can read more about the three wise men here : https://en.wikipedia.org/wiki/Biblical_Magi

thank you

No se a que te refieres exactamente , si al dia del rey de España ( que no se si hay un dia para el ) o a el dia de los Reyes Magos ( la Epifania ).