4 0 0 D O C U M E N T S 4 4 9 , 4 5 0 M A R C H 1 9 2 9 449. From Michele Besso Bern, 15 March 1929[1] Dear Albert, The newspapers remind us that you have just turned fifty. “Already fifty!” thought Mamie, who still sees you as you were when you were our colleague.[2] “Just fifty!” think I, at nearly seven years older, when I survey your monumental works. And I thank fate for having brought me near you, and that I did not waste this exceptional opportunity so completely as others did! At the same time, I am still sometimes nettled by Berisal because of the dangers to which I thoughtlessly exposed you back then, you and our fellow humans, whom you have endowed with great new insights.[3] Your incorruptible vision that belongs to those who are not fascinated by what is already considered certain, will still be preserved for decades for men whom it rightly astonishes, almost like a miracle. That this is a good wish is shown, for in- stance, by what Eiffel was able to do in his seventies and eighties in a branch of science that was entirely new for him.[4] On behalf of all of us, the family and the office, best regards, your Michele 450. From Max Planck et al. [Vienna,] 15 March 1929 Dear Colleague, How is your sixth decade going? We are thinking about you here in beautiful Vi- enna, with warm regards, your Max Planck Marga Planck[1] Hopefully you will come in the foreseeable future to Vienna, where we are very proud of Planck’s presence. Warm regards, Ehrenhaft[2] Dr. Olga Ehrenhaft-Steindler[3] Ella Dub[4]