Many and good questions for British Commonwealth collectors. I only have some answers. At the time of the Saxon conquest, both Saxons and Celts had a whole collection of kings, some controlling just a town and its immediate surroundings. In theory, these were loyal to a high king. In practice, even ealdormen (earls) were often autonomous, sometimes fighting the high king. So it was in Wales. Clans fought each other and Wales was united for only seven years under
Gruffydd ap Llywelyn (1039-1063), the first king of the Britons (Welshmen were known as Britons until the high middle ages). It was only through a complicated political compromise among the barons drawing up the Magna Charta that the title "Prince of Wales" came about. If Wales had not been
conquered by Edward I Longshanks shortly after, it is likely that the princely title would have been changed to king.
Meanwhile, Longshanks famously failed to subdue Scotland, giving rise to a Scottish kingdom under Robert the Bruce. Such fine distinctions were probably lost on Victorian historians and romanticists, who just knew that prince was a lower title than king.
Province is another historical misunderstanding. The word was invented by the
Romans and denoted an administrative unit of conquered territory. The conquest aspect was slowly lost, making a province no different from an English county.
Parliament is another word whose meaning has changed. Even the English version of Wikipedia treats it as a legislative assembly (the French version does better), but in the middle ages and renaissance, a parliament was simply an administrative council, implementing the orders of the ruler and a court of justice. Thus, the parliament of Burgundy was the address the French king used for raising taxes and the French king was the address the parliament of Burgundy would use to get a budget for their wishes (cahier de doléances, another term badly explained in the English version of Wikipedia). The role of the parliament in the Magna Charta was not to introduce democracy, but to introduce local government.
Traditional parliaments' only legislative role was to check the laws of the king against the local rights, prerogatives and customs. This right was exploited at the time of Charles I, effectively giving the English parliament the power of the purse. Further developments, such as the Hanoverian succession, secured the power of the English parliament and further eroded the power of the king to the point where it caught up and overtook the Dutch Estates General as an instrument of "democracy". The French revolution laid down a new parliamentary standard of power, not shared by the UK parliament, whose role is still determined by evolution from the parliaments of the middle ages, e.g. when it functions as a court in the highest instance.
While the role of parliaments in legislation was traditionally marginal, the role of
assemblies in Roman times was purely legislative. Assemblies may have been the most democratic institutions of Rome. Here also, the original meaning of words has been turned around, as in UK usage, assembly is most probably meant as a lower ranking body than parliament.
Peter