Precedence among European monarchies
The initial tension between the Carolingians and Byzantines over succession of the Roman Empire, dubbed by historians the problem of two emperors, largely faded away in the near-absence of a land border between the two entities.
In the early 14th century, the French monarchy's legal officials formalized this equality by claiming that the king has in his kingdom the same prerogatives as the emperor in the Empire (Rex est imperator in regno suo).
Before the Reformation, all western European powers acknowledged the supreme status of the Papacy and of its envoys, notwithstanding the longstanding conflict between popes and emperors that culminated in the Investiture Controversy.
A formal order of precedence was enunciated around 1504 by Pope Julius II, based on a combination of historical considerations (the older the realm, the higher the rank) and power positions.
The disputes were made visible by proceedings of the Papal court in Rome, where all the significant monarchies had ambassadors, and of occasional councils, as well as in third locations on occasion.
Similarly, the monarchs of Spain were malcontent with the seniority of those of France, following the end of the reign of Charles V who had outranked his French counterpart as Holy Roman Emperor.
[8] Spain contested French seniority for many generations: to avoid incidents, the respective ambassadors of the two countries often had to make sure they would not find themselves in the same place at the same time.
The generally held view that older monarchies deserved higher rank led to pseudo-historical claims of ancient origins, such as, for Sweden, Johannes Magnus's Historia de omnibus Gothorum Sueonumque regibus.
[14] In 1760, Sebastião José de Carvalho e Melo, 1st Marquis of Pombal, attempted to definitely resolve the issue of diplomatic precedence by denying any permanent seniority to envoys others than those of the Pope and Holy Roman Emperor.
The issue of precedence among ambassadors was settled at the Congress of Vienna, an outcome that was arguably enabled by the dissolution of the Holy Roman Empire in 1806 and the humbling of France following the Battle of Leipzig in 1813.
A "Regulation concerning the precedence of Diplomatic Agents", inspired by Talleyrand, was signed on 19 March 1815 and included as the last (17th) annex in the Congress's Final Act.
The rank of an ambassador was based on length of tenure, and specifically determined by the date of official notification of their arrival in a capital, except for papal envoys who retained senior status.
