Per https://news.yale.edu/2015/09/22/living-artifact-dutch-golde...
The bonds were issued by the Hoogheemraadschap Lekdijk Bovendams, a water board composed of landowners and leading citizens that managed dikes, canals, and a 20-mile stretch of the lower Rhine in Holland called the Lek. (Stichtse Rijnlanden is a successor organization to Lekdijk Bovendams.)