The letter that the famous anatomist Johann Friedrich Meckel, Sr. sent from Berlin on May 5, 1750 to the great Albrecht von Haller (at that time resident in Göttingen) contains the earliest reference to an unusual observation made by the former. Even today this observation is considered in the clinical literature to be the first description of a coarctation of the aorta. In fact, it is probably the first description of what is known today as Lutembacher syndrome.