01 December: "Weihnachten im Felde" (Christmas in the Field) - An Austro-Hungarian Christmas-card from 1916.

02 December: "Veselé Vánoce a Šťastný Nový Rok!" (Merry Christmas and Happy New Year!) - Austro-Hungarian Christmas-card in Czech in Czech.

03 December: "Boldog karácsonyi ünnepeket!" - Happy Christmas Holidays! - Austro-Hungarian Christmas-card in Hungarian.

04 December: A cheerful soldier with his arms full of presents, sausage, canned food and cognac from home. Austro-Hungarian Christmas-card.

05 December: "Herzliche Weihnachtsgrüße" (Best Christmas Greetings) - Austro-Hungarian Christmas-card.

06 December: Returning from leave with Christmas packages! Austro-Hungarian postcard, 1914.

07 December: "Stille Nacht, Heilige Nacht" - Silent Night, Holy Night!

08 December: "Wesołych Świąt!" (Merry Christmas!) Austro-Hungarian Christmas-card in Polish.

09 December: "Weihnacht 1916" (Christmas 1916) - Christmas-card from the Austro-Hungarian Generaloberst Eduard von Böhm-Ermolli's 2nd Army.

10 December: "Katonák Karácsonya" (Christmas Soldiers) - Austro-Hungarian Christmas-card In Hungarian.

"Candle flames on the slender branches of the fir-trees,
Above their heads lights the fire of the shrapnel a festive flame.
The sound of a cannon harmonizes, while they are going, marching,
The Christmas Carol sounds on their lips."

Thanks to @BennoSzepesi for the translation!