Stanisław August Poniatowski

Stanisław II August (born Stanisław Antoni Poniatowski; 17 January 1732 – 12 February 1798), known also by his regnal Latin name Stanislaus II Augustus, and as Stanisław August Poniatowski (Lithuanian: Stanislovas Augustas Poniatovskis), was King of Poland and Grand Duke of Lithuania from 1764 to 1795, and the last monarch of the Polish–Lithuanian Commonwealth. Born into wealthy Polish aristocracy, Poniatowski arrived as a diplomat at the Russian imperial court in Saint Petersburg in 1755 at the age of 22 and became intimately involved with the future empress Catherine the Great.

Source: Wikipedia — Stanisław August Poniatowski (CC BY-SA 4.0)