The first memorial service for the dead of Buchenwald took place on the camp muster ground on the evening of 19 April 1945. It had been organized by survivors on behalf of the International Camp Committee. A wooden obelisk made in the camp workshops served as a temporary memorial. It bore the inscription “K.L.B. 51.000”, signifying the estimated number of persons who had lost their lives while registered as Buchenwald inmates.
To music played by the camp orchestra, the survivors filed onto the muster ground, divided by nation and grouped in blocks. A previously composed commemorative address was read out in Russian, Polish, German, French, Czech and English. It ended with a joint pledge: “The destruction of Nazism, down to its roots, is our motto. To build a new world of peace and freedom is our ideal.” Today this pledge is known as the Oath of Buchenwald.
Source: Camp newspaper Buchenwalder Nachrichten, 20 April 1945 (Buchenwald Memorial).