Paul I of Russia
Paul I (; "Pavel Petrovich") ( – ) reigned as Emperor of Russia between 1796 and 1801. Officially, he was the only son of Peter III and Catherine the Great, though Catherine hinted that he was fathered by her lover Sergei Saltykov, who also had Romanov blood, being a descendant of the first Romanov tsar's sister, Tatiana Feodorovna Romanova.
Vincenzo Brenna
Vincenzo Brenna (1747 – May 17, 1820) was an Italian architect and painter who was the house architect of Paul I of Russia. Brenna was hired by Paul and his spouse Maria Fyodorovna as interior decorator in 1781 and by the end of 1780s became the couple's leading architect. Brenna worked on Pavlovsk Palace and Gatchina palaces, rebuilt Saint Isaac's Cathedral, and most notably created Saint Michael's Castle in Saint Petersburg. Most of his architectural works were created concurrently during Paul's brief reign (November 1796 – March 1801). Soon after Paul was murdered in a palace coup Brenna, renowned for fraud and embezzlement barely tolerated by his late patron, retired and left Russia for an uneventful life in Saxony.