From the 16th century onwards, the German academy offered a home for the most intensive reflection about modern statehood. German professors used the vocabulary of ius naturae et gentium (law of nature and of nations) to adapt the insights they had applied to the constitution of the Roman–German Empire to the world of European diplomacy in general. Statehood, it was suggested, was an instrument for the community to govern its affairs in a rational way. The notion of the Christian paterfamilias was given a secular meaning in the theory of the ruler as the manager of the state-machine that was to be operated under the instructions produced by a rational science of natural law. The fact that the practice of 18th-century diplomacy was hard to confine within the strictures of natural law theory, gave legal doctrine an often sceptical tone that pushed it ever closer to raison d’état.