When Luxembourg was invaded and annexed by Nazi Germany in 1940, a national consciousness started to come about. From 1941 onwards, the first resistance groups such as the Letzeburger Ro'de Lé'w or the PI-Men were founded. Operating underground, they secretly worked against the German occupation, helping to bring political refugees and those trying to avoid being conscripted into the German forces across the border, and put out patriotic leaflets (often depicting Grand Duchess Charlotte) encouraging the population of Luxembourg to pull through.