Einstein's fiftieth birthday appears to have been more of a cause for celebration by others than for himself. Having lived under intense scrutiny from the (mostly) adoring public and intrusive journalists for 10 years already, Einstein made valiant efforts to avoid attention from the press on this momentous occasion. He was particularly keen to avoid the hullabaloo ratcheting up for his fiftieth in Berlin. The day before his birthday, a New York Times article, Einstein Flees Berlin to Avoid Being Feted reported that: "To evade all ceremonies and celebrations, he suddenly departed from Berlin last night and left no address. Even his most intimate friends will not know his whereabouts."
Einstein's decision allowed him and his family relative respite. While Einstein hid in a countryside retreat, "[t]elegraph messengers, postmen and delivery boys had to wait in line hours today in front of the house No. 5 Haberland Strasse, delivering congratulations and gifts to Albert Einstein on the occasion of his fiftieth birthday today," according to the March 15 issue of the Jewish Daily Bulletin. Above is one card of the many that Einstein received on and around his birthday; it was made by a pupil at the Jüdische Knabenschule, Hermann Küchler.
After all, an intrepid reporter did find Einstein – in a leafy neighborhood of Berlin called Gatow, half an hour from the city center. A report for avid fans, Einstein Found Hiding on his Birthday, in the March 15 edition of The New York Times provides a gamut of details from the color of his sweater to the menu for his birthday dinner and the array of gifts found on a side table. Happy reading, on this, the 140th anniversary of Einstein's birth!
Einstein's 50th will be covered in Volume 16 of The Collected Papers of Albert Einstein. Of the many and varied resources we refer to for historical research, the two used for this web post were: The New York Times archive: Times Machine and the Jewish Telegraphic Agency Archive.
Access to the Times Machine requires a subscription to The New York Times. The card, item number 30-349, is held at the Albert Einstein Archives at HUJI.