FRET stands for Förster resonance energy transfer. While much is known about resonance energy transfer, much less is known about Förster–apart from the fact that he was the one who translated FRET from a theoretical phenomenon into a broadly usable method for investigating and understanding biomolecular interactions on the nanoscale. Arguably, a major reason for the limited recognition of Theodor Förster is his scientific career during the Nazi time in Germany about which little is documented. By reviewing documents from different archives, this Viewpoint Article–on the occasion of the 50^th anniversary of his death–sheds some light on Förster's life from 1933 to 1951 and describes how a young scientist struggled during dark times in history.