Sweetbread is indeed commonly found in traditional European cookery and many books refer to the use of this ingredient, including for the preparation of stews made with offal. In German it is called "Kalbsbries", in French "Ris de veau". A French book originally published in 1928 (Ali-Bab, an alias used by Henri Babinski: Gastronomie Pratique) refers to a recipe involving sweetbread but also the spinal marrow ("cord").
Sweetbread is indeed frequently encountered in traditional European cooking and numerous books mention its use, including for preparing stews made with offal. In German it is known as "Kalbsbries", in French "Ris de veau". A French book first published in 1928 (Ali-Bab, an alias used by Henri Babinski: Gastronomie Pratique) mentions a recipe that includes sweetbread but also spinal marrow ("cord").