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.
... 1973)
March 6 - Joseph Schmidt[?], tenor (+ 1942)
March 7 - Reinhard Heydrich, Nazi official
March 20 - B. F. Skinner, behavioral psychologist (+ 1990)
March 23 - ...