He left Paris probably on the 5th of April 1728 for Vienna, and arrived in Vienna in the first days of May. He spent a few weeks in the northern parts (today territory of Slovakia i.e. of the Slovak Republic) of the “historical Hungary” (in Hungarian: Történeti Magyarország, in French: Hongrie historique). On the 26th of June he was back in Vienna, and finally he left the (imperial) city on the 9th of July.
It is worth noting that the father of Montesquieu, decades earlier, in 1685, as the soldier (officer) of the Prince de Conti, had already traveled in Hungary.
Unfortunately, the notes of Montesquieu on his journey in Hungary did not survive, but after returning home he compiled his notes entitled Mémoires sur les Mines de Hongrie et Hartz in which we can find interesting and important data (informations) concerning the Kingdom of Hungary. We know for sure, that he visited in Pozsony – then (until 1848) the capital of Hungary – (in Slovakian: Bratislava, in German: Pressburg, in Latin: Posonium, in French: Presbourg) the National Assembly (Diet) of the Kingdom of Hungary (in Latin: Diaeta), and then Körmöcbánya (in Slovakian: Kremnica, in German: Kremnitz, in Latin: Cremnicium), Besztercebánya (in Slovakian: Banská Bystrica, in German: Neusohl, in Latin: Neosolium), and Újbánya (in Slovakian: Nová Ba?a, in German: Königsberg, in Latin: Regiomontanum), that is to say the cities of Upper Hungary (in French: Haute Hongrie, in Hungarian: Felvidék), or more precisely, some, although undoubtedly the most important ones, of them.
In the above-mentioned notes we find details like this – in English translation: “In Hungary, you need only to plant the corn in the ground and it grows. It is so, because the lands of Hungary are not under very good cultivation and there the fields rest more.” Or: “There are three greatly significant places in Hungary: Eszék (in Croatian: Osijek, in German: Esseg), which, I think, lies where the Drava and the Danube flow into each other; Belgrade (in Hungarian: Nándorfehérvár) and Temesvár (in Romanian: Timi?oara, in German: Temeschwar); Orsova (in Romanian: Or?ova) is, on the shore of the Danube, supplied constantly with artillery batteries which keep the Turks i.e. Ottomans from advancing.”