Question: What dissolved the privileges of the birth empire of Alexey Brodovitch, the kingdom acquiring some Thuringian territory or Habsburg Monarchy?

Passages:
Alexey Brodovitch was born in Ogolichi, Russian Empire (now Belarus) to a wealthy family in 1898. His father, Vyacheslav or Cheslau Brodovitch, was a respected physician, psychiatrist and huntsman. His mother was an amateur painter. During the Russo-Japanese War, his family moved to Moscow, where his father worked in a hospital for Japanese prisoners. Alexey was sent to study at the Prince Tenisheff School, a prestigious institution in Saint Petersburg, with the intentions of eventually enrolling in the Imperial Art Academy. He had no formal training in art through his childhood, but often sketched noble profiles in the audience at concerts in the city. Some reordering of the Thuringian states occurred during the German Mediatisation from 1795 to 1814, and the territory was included within the Napoleonic Confederation of the Rhine organized in 1806. The 1815 Congress of Vienna confirmed these changes and the Thuringian states' inclusion in the German Confederation; the Kingdom of Prussia also acquired some Thuringian territory and administered it within the Province of Saxony. The Thuringian duchies which became part of the German Empire in 1871 during the Prussian-led unification of Germany were Saxe-Weimar-Eisenach, Saxe-Meiningen, Saxe-Altenburg, Saxe-Coburg-Gotha, Schwarzburg-Sondershausen, Schwarzburg-Rudolstadt and the two principalities of Reuss Elder Line and Reuss Younger Line. In 1920, after World War I, these small states merged into one state, called Thuringia; only Saxe-Coburg voted to join Bavaria instead. Weimar became the new capital of Thuringia. The coat of arms of this new state was simpler than they had been previously. Poland's nobility were also more numerous than those of all other European countries, constituting some 10–12% of the total population of historic Polish–Lithuanian Commonwealth also some 10–12% among ethnic Poles on ethnic Polish lands (part of Commonwealth), but up to 25% of all Poles worldwide (szlachta could dispose more of resources to travels and/or conquering), while in some poorer regions (e.g., Mazowsze, the area centred on Warsaw) nearly 30%. However, according to  szlachta comprised around 8% of the total population in 1791 (up from 6.6% in the 16th century), and no more than 16% of the Roman Catholic (mostly ethnically Polish) population. It should be noted, though, that Polish szlachta usually incorporated most local nobility from the areas that were absorbed by Poland–Lithuania (Ruthenian boyars, Livonian nobles, etc.) By contrast, the nobilities of other European countries, except for Spain, amounted to a mere 1–3%, however the era of sovereign rules of Polish nobility ended earlier than in other countries (excluding France) yet in 1795 (see: Partitions of Poland), since then their legitimation and future fate depended on legislature and procedures of Russian Empire, Kingdom of Prussia or Habsburg Monarchy. Gradually their privileges were under further limitations to be completely dissolved by March Constitution of Poland in 1921.

Supporting sentences:
The 1815 Congress of Vienna confirmed these changes and the Thuringian states' inclusion in the German Confederation; the Kingdom of Prussia also acquired some Thuringian territory and administered it within the Province of Saxony. Gradually their privileges were under further limitations to be completely dissolved by March Constitution of Poland in 1921.