Albert Schweitzer's participation in the Lindau Nobel Laureate Meeting in 1954, inspired Werner Heisenberg to “rethink the humanitarian side of science.” Upon his initiative, all Nobel Laureates whose work dealt with nuclear research were invited to the 1955 Lindau Meeting. Jointly they drafted an appeal to political decision-makers in East and West “to reject force as the ultimate instrument of politics.” They issued a warning against the use of atomic weapons. This appeal, known as the Mainau declaration, initially bore the signatures of eighteen Nobel Laureates.