A Grand Duchy is a territory ruled by a Grand Duke or Grand Duchess, which is a rank above a duke but below a king. This form of governance often exists within a larger kingdom or empire. Grand Duchies can have varying degrees of autonomy, with some having their own laws and governance structures while still being subject to a higher authority. Historically, notable examples of Grand Duchies include the Grand Duchy of Luxembourg and the Grand Duchy of Finland. These regions often have rich cultural heritages and unique identities, contributing to the diversity of the countries they are part of.