Operation Military_operation Tannenberg ( ) was a codename for one of the extermination actions by Nazi Germany that was directed Aiming at the Poles during the opening Openness stages of World War II in Europe , as part of the `` Generalplan Ost '' for the German colonization of the East .

that up to 20,000 Germans living in Poland belonged to organizations involved Cause_to_be_included in various forms of subversion. < ref name= '' polityka.pl/historia '' > < /ref > Operation Tannenberg was followed by the `` Intelligenzaktion '' , a second phase of the `` Unternehmen Tannenberg '' directed by Heydrich 's `` Sonderreferat '' from Berlin , which lasted until January 1940 .

that up to 20,000 Germans living in Poland belonged to organizations involved Cause_to_be_included in various forms of subversion. < ref name= '' polityka.pl/historia '' > < /ref > Operation Tannenberg was followed by the `` Intelligenzaktion '' , a second phase of the `` Unternehmen Tannenberg '' directed by Heydrich 's `` Sonderreferat '' from Berlin , which lasted until January 1940 .

As there were no more sufficient forces for the defence of the former front line at Narva in July , the army group began Process_start preparations for the withdrawal of their forces to the Tannenberg defence Defending line at the Sinimäed Hills 16 kilometres from Narva .

The `` Intelligenzaktion '' was a major step to implementing Action `` Sonderaktion Tannenberg '' ( Operation Tannenberg ) , the installation of Nazi policemen and functionaries — from the SiPo ( composed of the Kripo and Gestapo ) , and the SD — to manage Hold the occupation and facilitate Cause_to_make_progress the realisation of `` Generalplan Ost '' , the German colonization of Poland .

The `` Intelligenzaktion '' was a major step to implementing Action `` Sonderaktion Tannenberg '' ( Operation Tannenberg ) , the installation of Nazi policemen and functionaries — from the SiPo ( composed of the Kripo and Gestapo ) , and the SD — to manage Hold the occupation and facilitate Cause_to_make_progress the realisation of `` Generalplan Ost '' , the German colonization of Poland .

After the truce expired Process_end in June 1410 , the military-religious monks were decisively defeated Conquering in the Battle of Grunwald ( Tannenberg ) , one of the largest battles in medieval Europe .