Poland. (Prisoner of War Mail). 1919. Envelope headed 'Franc de Port' addressed to 'Comite International de la Croix Rouge, Agence Internationale des Prisonniers de Guerre' bearing Poland Yvert 151, 20f blue tied by Wolsztynie/ hand-stamp with 'Kontrols Poczi/ Wolsztynie' in carmine and octagonal 'Przegladane/ Przez Wladze/ Wojskowa' in violet on face and 'E.S./ F.F./ No B -K. 5728' label in turquoise with framed 'Vendue Par/ L' Agence Internationale/ Der Prisonniers de Guerre.' Very fine.