Petty kingdom

A petty kingdom is a kingdom described as minor or "petty" by contrast to an empire or unified kingdom that either preceded or succeeded it (e.g. the numerous kingdoms of Anglo-Saxon England unified into the Kingdom of England in the 10th century, or the numerous Gaelic kingdoms of Ireland unified under the Kingdom of England as the Kingdom of Ireland in the 16th). Alternatively, a petty kingdom would be a minor kingdom in the immediate vicinity of larger kingdoms, such as the medieval Kingdom of Mann and the Isles relative to the kingdoms of Scotland or England or the Viking kingdoms of Scandinavia.

In the context of the Dark Ages or the prehistoric Iron Age such minor kingdoms are also known as tribal kingdoms. In the parallel Southeast Asian political model, petty kingdoms were known as Mueang.

By the European High Middle Ages, many post-Roman Early Middle Ages petty kingdoms had evolved into principalities, grand duchies, or duchies. By the European Early Modern era, many of these principalities had been mediatized into larger monarchies, but the ruling families were not considered morganatic for marriage considerations, and ranked equal to royal families in society. The various small states of the Holy Roman Empire are generally not considered to be petty kingdoms since they were at least nominally subject to the Holy Roman Emperor and not fully independent.

...
Wikipedia