The loss of the greatest pearl in the Habsburg crown, Silesia, was very painful for Maria Theresa. Already in Ferdinand's time the growth of the nobility's estate economy had increased the need for peasant labour, see part V - The law on serf labour in the Duchy of Opole and Racibórz of March 1562. In those years the easiest way to raise output was to place the burden on the subject population. This, however, caused peasants to flee, so special legislation was issued, the “Robotordnung”, the first in the whole empire for the Duchy of Opole, together with a ban on leaving one's place of residence. Runaways were hunted down and made an example of.
Calling Silesia a pearl in the crown is justified here. The Habsburg state was large, and losing 15% of all annual revenue from our land alone was a great loss. G. Otruba “Schlesien im System des österreichischen Merkantilismus” ... The charges for state purposes amounted to 2.6 million guilders, about 15% of all Habsburg revenue in 1740.
When Frederick II crossed the borders in December 1740, the passivity of the oppressed Silesians during his march through Silesia was not without significance. The mood of the inhabitants was calmed by Frederick's promises: no hostility from his army towards the inhabitants and the preservation of all privileges and freedoms. So the towns surrendered without resistance. A gesture by the Prussian king was to invite the Silesian nobility from the occupied areas and to receive them with royal hospitality.
The second war began with Frederick II's entry into Bohemia in August 1744. It was followed by a withdrawal and a new meeting of the two armies (4.6.1745) near Strzegom, and the Peace of Dresden in 1745 strengthened Prussian rule over Silesia. Using its military and economic potential raised Prussia to second place (after Austria) in the whole German Reich. The German Empire now had two rival dynasties, Austria with the Habsburgs and Prussia with the Hohenzollerns, and our Silesian lands were of key importance in this.
Silesia in the Prussian state.