This paper presents the hitherto unpublished seal of the Phanariot-Greek Voivod of Moldavia Constantine Ypsilantis (r. 1799-1801) in its historical and sigillographic context. While the focus lies on Moldavia, seals from the other Danubian Principality Wallachia will also serve as items for comparison. The aim is to describe the seal as set in the sigillographic tradition of the area and at the same time analyzing its peculiarities, including the protective box. Ypsilantis reign is set towards the end of Ottoman rule in the Moldavia and Wallachia, in a time of increasing Western and Russian influence, but the seal is firmly embedded in the tradition of voievodal titulary and the heraldry of the time. However, differences between the heraldic depictions on the seal and its protective lid show that even in a princely court around 1800, quite important variations such as the missing of some symbols on the arms were permissible.