King Christian X. According to popular legend, King Christian X chose to wear a yellow star in support of the Danish Jews during the Nazi occupation of Denmark. In another version, the Danish people decided to wear a yellow star for the same reason. Both of these stories are fictional. However, the legend conveys an important historical truth: both the King and the Danish people stood by their Jewish citizens and were instrumental in saving the overwhelming majority of them from Nazi persecution and death.
USHMM, courtesy of Leo Goldberger