poor health, due primarily to malnutrition, when he was left behind in Auschwitz with the rest of those in the sick barracks, when the Nazis evacuated all the other prisoners on a death march. He survived until the Russians liberated Auschwitz shortly afterward. In 1953, he married Elfride "Fritzi" Markovits-Geiringer, an Auschwitz survivor who lost her first husband and her son when they, too, were sent on a death march out of Auschwitz, and whose daughter Eva, also a survivor, was a neighborhood friend of the Frank sisters'. Otto devoted his life to spreading the message of his daughter and her diary, as well as to defending it against Neo-Nazi claims that it was a forgery or fake. He died in Birsfelden, Switzerland from lung cancer, on 19 August 1980 at the age of 91. His widow, Fritzi, continued his work until her own death in October 1998. Edith Frank (16 January 1900 – 6 January 1945; Anne and Margot's mother, wife of Otto) was left behind in Auschwitz-Birkenau when her daughters and Auguste van Pels were transferred to Bergen-Belsen, as her health had started to deteriorate. Witnesses reported that her despair at being separated from her daughters led to an emotional breakdown. They described her searching for her daughters endlessly and said that she seemed to not understand that they had gone, although she had seen them board the train that took them out of the camp. They also said that she began to hoard what little food she could obtain, hiding it under her bunk to give to Anne and Margot when she saw them. They said that Edith Frank told them Anne and Margot needed the food more than she did, and she therefore refused to eat it. She died on 6 January 1945 from starvation and exhaustion, ten days before her 45th birthday and 21 days before the camp was liberated. Margot Frank (16 February 1926 – February 1945) died of typhus in Bergen-Belsen. According to recollections from several eyewitnesses, this occurred "a few days" before Anne's death, most likely in early-mid February 1945, though like Anne's death, the exact date is not known. The Van Pels family joined the Franks in their hiding place in concealed rooms at the rear of Otto Frank's office building, on 13 July 1942. Anne gave the van Pels family a pseudonym in her diary (as she did for most