Great, but it was Joseph II that transformed ‘militar grenze’ into a sophisticated intelligence rampart : “The sanitary cordon that Emperor Joseph I built along the Habsburg-Ottoman frontier was one of the most successful quarantine systems ever created” https://www.wsj.com/articles/emperor-josephs-solution-to-coronavirus-11586214561

By extending the military frontier to Transylvania Empress Maria Theresia and Emperor Joseph II discreetly addressed the increasing footprint of the Romanov Russian Empire in the region.

It was actually Joseph II who traveled disguised for three times to Transylvania, becoming not just an enlighted monarch intelligence gatherer, but also a myth for Romanians until 1918 and even beyond.

It is rather sad that his monumental work (personal reports and secret letters) to Vienna were not translated yet in English, since they are a masterpiece of strategic thinking in action.

End of thread & main lesson from Habsburg ‘militar grenze’ system: no ‘sanitary cordon’/quarantine can be succesful as long as it is not designed with a strategic meaning.