In the year 1308, the House of Luxembourg came to the helm of the Holy Roman Empire and in 1310, of the Kingdom of Bohemia. For more than one century, until the death of Sigismund of Luxembourg (1437), the Luxembourgs became one of the most powerful ruling families at the European level. They administered a vast complex of territories distant from their homeland, the county – later duchy – of Luxembourg. The present project intends to examine how the central authority dealt with this accruing degree of authority, and how they managed to rule with the use of different institutional and non-formal instruments and to cooperate with different political bodies at three levels: the county, the kingdom and the empire. Hence its dual focus: on the figure of the ruler on the one hand, and on the political society on the other, including the linkage between these two distinct parties on the three aforementioned levels. The difficulty, but also the interest of this research, stems from the extensive gallery of sovereigns, the wide range of positions involved, and from the diversity of political communities spread across so many territories in Western and Central Europe. Rather than presenting the medieval ruler as the sole supreme agent of politics, this research will take into serious account the pivotal linkage between ‘consensus’ and ‘auctoritas’, with a view to exposing the idea of a contract between ruler and political society. Three research areas will be of central concern: 1. the transcendent authority of the sovereign at the central level, and the functioning of his court and administration; 2. the modes of government at the regional level, and the spectrum of solutions from delegation to participation, including collaboration with local elites; 3. the decision-making process and the necessity of reaching consensus, a general atmosphere of unity and unanimity, instrumental in its enforcement.This type of historical enquiry would ultimately be of relevance to analysis of 21st-century multi-level governance, where all political decisions presuppose the negotiation of consensus between widely varying levels of authority.