The preparation for the extermination of the Jews of the Generalgouvernement had actually started months before the "Wannsee Conference". A special organisation was formed which came to be called “Aktion Reinhard”, probably named in honour of Reinhard Heydrich after his assassination in Prague.
This organisation was established under the command of SS and Police Leader Lublin Odilo Globocnik, who had been appointed by Himmler, to manage the murder programme.
On 20/21 July 1941, Himmler visited Globocnik in Lublin and decided to enlarge and extend the SS economic enterprises there. In an official note, Himmler instructed the SSPF Lublin to establish a concentration camp in the city for 25,000 to 50,000 prisoners, with a view to employing them in the workshops and on the building sites of the SS and Police.
Towards the end of 1941 it was decided that the KL Majdanek would also serve as a camp for Soviet POWs. He also ordered the expansion of the work camp 7 Lipowa Street, and the settlement of Germans in the Zamosc region.