International audience Measuring the absolute: it is through this concept that the jurists of Louis XIII and Richelieu significantly contributed to the elaboration of a State based on the rule of law. The successors of the Légistes and the Politiques defined the foundations, criteria and limits of this notion of absolute, which they now had to measure. Being at the heart of the process, sovereignty was used as a genuine weapon. Throughout the first half of the reign, sovereignty, in its defensive sense, combined both the ideas of unity and independence. However, as of 1630, sovereignty became more offensive in nature in response to political radicalisation. Internal sovereignty thus followed its course, explicitly adding the concept of indivisibility to the structuring principle of unity. External sovereignty, on the other hand, underwent major changes: self-construction could no longer rely solely on implicit differentiation with others and it now implied having claims over other States. In doing so, internal and external sovereignty merged into souveraineté-puissance more so than into souveraineté-liberté; bearing in mind that today, the former refers to internal affairs and the latter to foreign affairs. It was not until 1648 and the peace treaties of Westphalia that interstate relations manifested a desire of stability. In other words, if the State emerged against other State entities, it grew stronger alongside them, within a pacified context. The affirmation of souveraineté-puissance depended on the prior constitution of a civil trinity of sorts, made-up of the now strengthened king, sovereignty and the State. The law and the philosophy of reason of State naturally ensued from this parameter, as they both shared the objective of controlling and preserving this so-denominated trinity. Whether one is talking about ordinary cases or those of the exceptionally ordinary kind, the very essence of the State is to be found in force and law. The jurists of Louis XIII and Richelieu thus focused on the rights of the King, both from a quantitative and qualitative angle. In doing so, they set the standard for measuring the absolute. The political radicalisation of the second half of the reign had an accelerating effect on this matter, as the law was now to provide the framework, or – at the very least – the justification of politics. Fully aware that measuring the absolute required some points of reference, these jurists used the law in such a manner as to strengthen the trinity. If defining the absolute meant setting its boundaries, jurists allowed themselves the right to push back these said-boundaries in instances where the theory they were defending demanded it. Thus the measure of the absolute was that which jurists consented to offer. The story of Louis XIII’s reign tells of the route from majesty to dignity. Ultimately, the rights of the King evolved into authentic State law. More than State theorisation, a firmly-established State theory now existed.