Denmark has issued stamps since 1851. The first person to be featured on a Danish stamp was King Christian IX. The years appearing after each name refer to when that person was first featured on a stamp.
... also:
1904 in film
1904 in literature
1904 in music
1904 in sports
Events:
January 7 - The distress signal[?] "CQD" is established only to be replaced two ...