Card No. 509 (2o Livre D'Or)
The Chocolat Guérin-Boutron company published this striking picture of the teenage Marie-Adélaïde with long flowing hair on one of its many delightful advertising cards. And then on June 14, 1908 Luxembourg 'issued' these four poster stamps with a similar portrait of the future Grand Duchess. Prifix somewhat cryptically refers to these as "précurseurs de caritas sans valeur d’affranchissement."
While they had no franking value, we find them adorning covers and cards, as shown below:
Echternach, March 15, 1909 to Antwerp, Belgium
Dommeldange, June 15, 1908, to Brabant, Belgium
(Second day cover)
But, alas! When the next Caritas precursors appeared in 1914 showing the six princesses (the 'Colonies de Vacances' set), Marie's long hair had been shorn. (That's Marie second from the right.)