Upvote:-2
I do not think, there was such a law, but the emperors did not have any interest in promoting their (potential) enemies within the Empire. Therefore it was easier for prince-elector of Brandenburg (or for duche of Savoy) to use the territorial gains outside of the borders of the HRE for proclaiming themselves kings of these territories.
Upvote:0
Thatβs true. No kings were permitted within the Holy Roman Empire, except for four existing titles - Bohemia and Moravia were two. Frederich had to call himself originally King in Prussia to get around this (part of Prussia was in the Empire therefore he couldnβt be King of it, and part was subject to Polish rule). Only later did he upgrade himself to King of Prussia. Norman Davies has published some good material on this topic.
Upvote:2
The Golden Bull of 1356 did not prohibit explicitly the creation of new kingdoms, but
a) there were many rules regarding the precedence of the existing electors
b) the king of Bohemia had some special status due to being the only king.
A new kingdom would imply on i) revising all the privileges and precedence rules to include the new king, which would obviously upset someone; OR ii) letting the new king with lesser privileges than the other electors and the king of Bohemia, which would appear very demeaning to the new king.
Some quotations from the Golden Rule to support these assertions:
We decree, moreover, that, as often as an imperial court shall henceforth chance to be held, in every assembly,-in council, namely, at table or in any place whatsoever where the emperor or king of the Romans shall happen to sit with the prince electors, on the right side of the emperor or king of the Romans there shall sit immediately after the archbishop of Mainz or the archbishop of Cologne-whichever, namely, shall happen at that time, according to the place or province, following the tenor of his privilege, to sit at the right hand of the emperor-first, the king of Bohemia, as he is a crowned and anointed prince, and secondly, the count palatine of the Rhine. But on the left side, immediately after whichever of the aforesaid archbishops shall happen to sit on the left, the duke of Saxony shall have the first, and, after him, the margrave of Brandenburg the second place.
So, if you create a second king, who is going to sit at the right of the emperor? Or, who is going to tell the Duke of Saxony that he is not going to be the first at the left of the emperor any more?
We decree that, in holding an imperial court, whenever in future one shall chance to be held, the aforesaid prince electors, ecclesiastical and secular, shall immutably hold their positions on the right and on the left-according to the prescribed order and manner. And no other prince of whatever standing, dignity, pre-eminence or condition be may be, shall in any way be preferred to them or anyone of them, in any acts relating to that court; in going there, while sitting or while standing. And it is distinctly declared that especially the king of Bohemia shall, in the holding of such courts, in each and every place and act aforesaid, immutably precede any other king, with whatsoever special prerogative of dignity he may be adorned, no matter what the occasion or cause for which he may happen to come or to be present.
The law above even considers the case of a new kingdom being created. So, to accommodate the new king they would have to change the "immutable" precedence rules, and end the privileges of the King of Bohemia, OR the new king would have to accept having less privileges than the King of Bohemia and even, in some aspects, the other non-king electors.
In short, supposing you want a new crown to a new king, who is going to convince whom to accept lesser precedence or lesser privileges?
You can continue reading the Golden Bull to sort the many precedence rules about the various ceremonies during the Diet, coronations and the elections, and the special legal privileges to Bohemia and some of the non-king electors. Imagine the pain of having to change every little detail of these intricate rules - the Emperor would need to have a very good reason to do that.
Upvote:3
Not aware of any law per say, but note that the HRE itself technically was an elective monarchy. The electors would actually elect the King of the Romans rather than the Holy Roman Emperor:
The title was predominantly a claim to become Holy Roman Emperor, which also had a religious aspect in contemporary views of the Middle Ages and was dependent upon coronation by the Pope.
As for the Kingdom of Bohemia, you can think of it as a promotion for good services rendered:
The kingdom was formally established in 1198 by PΕemysl Ottokar I, who had his status acknowledged by Philip of Swabia, elected King of the Romans, in return for his support against the rival Emperor Otto IV. In 1204 Ottokar's royal status was accepted by Otto IV as well as by Pope Innocent III. It was officially recognized in 1212 by the Golden Bull of Sicily issued by Emperor Frederick II, elevating the Duchy of Bohemia to Kingdom status.
Under these terms, the Czech king was to be exempt from all future obligations to the Holy Roman Empire except for participation in the imperial councils. The imperial prerogative to ratify each Bohemian ruler and to appoint the bishop of Prague was revoked. The king's successor was his son Wenceslaus I, from his second marriage.
With respect to "promoting" nobles to a new title, you may also find this related question of interest:
Upvote:8
Originally, there were seven electors of the Holy Roman Emperor, three ecclesiastical, and four temporal. These were called "prince-electors," and were the highest ranking dignitaries of the Holy Roman Empire other than the Emperor himself.
The three ecclesiastical electors were the archbishops of Mainz, Trier, and Cologne. The four temporal electors were the heads of state of Bohemia, Brandenburg, Saxony, and the Palatinate. Of those, only the head of Bohemia was a "king," making Bohemia a kingdom. The head of Palatinate was a Count, of Brandenburg was a Margrave, and of Saxony was a Duke.
Much later, the heads of Brandenburg and Saxony also styled themselves "kings." That is, the Elector of Brandenburg became "King in Prussia" (and later King of Prussia) after that domain merged with Prussia, while the Elector of Saxony also became King of Poland in a "personal union." But there were no "second" kingdoms totally within the Holy Roman Empire itself. And in the 17th century, Bohemia became part of the Austro-Hungarian empire, part of which was not in the Holy Roman Empire.