In the 1950s and 1960s, Meitner enjoyed visiting Germany and staying with Hahn and his family for several days on different occasions. Hahn wrote in his memoirs that he and Meitner had remained lifelong close friends. Even though their friendship was full of trials, arguably more so experienced by Meitner, she "never voiced anything but deep affection for Hahn". On occasions such as their 70th, 75th, 80th and 85th birthdays, they addressed recollections in each other's honour. Hahn emphasised Meitner's intellectual productivity, and work such as her research on the nuclear shell model, always passing over the reasons for her move to Sweden as quickly as possible. She emphasised Hahn's personal qualities, his charm and musical ability.