Subsequent heirship (Vor- und Nacherbschaft)

In some cases the testator may wish to have an influence on the fate of the inheritance after his death, e.g. because he names his second wife sole heir but does not want that she passes the estate to her children from a prior marriage.  In order to achieve this, the testator may provide, that the estate first passes to the preliminary heir (Vorerbe) and upon a certain condition, to the subsequent heir (Nacherbe). See § 2100 BGB.