Can anyone please help translate this :

"Leutnant Ahammer zür Erinnerung an
ernst und frohe Stunder im Kameradenkreis
Athen, im Herbst 1941 3./Pi. 659"

Thanks for your help.

"Leutnant Ahammer zur Erinnerung an ernste und frohe Stunden im Kameradenkreis"

"Lieutenant Ahammer in remembrance of severe (serious) and happy hours in the circle of comrades
Athens, in fall 1941"

The abbreviation "3./Pi. 659" means "3. Pionier-Bataillon 659" (3rd sapper battallion 659). It was stationed in fall 1941 in Greece.

Here some detailed information regardig the battalion, unfortunately in German only.

http://www.lexikon-der-wehrmacht.de/Gliederungen/PionierBat/PiBat659-R.htm

thank you ivbaust for your help !