For me, philately is the study and enjoyment of miniature art.  You'll surely understand my sentiment if you collect stamps engraved by Ferdinand Schirnböck (1859-1930), Europe's master engraver of the early 1900s.  And the Marie-Adélaïde definitives, issued by Luxembourg in 1914, 1915 and 1917, might be his finest achievement.  Even though Grand Duchess Marie- Adélaïde abdicated in January 1919, these stamps were used well into the 1920s, retaining postal validity until July 1, 1928.  However you collect them, you will never tire of viewing Schirnböck's masterful engraving of Marie-Adélaïde when she was Luxembourg's young, enigmatic monarch!