Who is considered an heir and how the estate is distributed affects most people at some point in their lives. Modern inheritance law is largely based on the 1928 Inheritance Act. There are also current rules that are even older. This means that inheritance law is based on a different social model than today and that later modern rules have been added to a very old structure. The rules of inheritance law are still based on a principle of affinity based on blood ties or a family based on marriage. Today there are many cohabitation constellations which mean that the concept of the family can no longer be regarded as homogeneous and clear. This has resulted in ambiguities and unpredictable consequences for the parties involved, such as divorced people indirectly inheriting each other. Societal changes have also affected the perception of protection value and fairness. The surviving spouse's right of inheritance means that breast heirs are treated differently and joint children may even be deprived of an inheritance. Inheritance law is based on ideas from a different social structure than the one we have today and is an unexplored area of law in modern times. New knowledge is added by highlighting the law of succession from a historical, present and future perspective in order to highlight specific problems and discuss possible future solutions.