The architect of XXX was whom?
Gatchina Palace
The Great Gatchina Palace (Russian: Большой Гатчинский дворец) was built in 1766--1781 in Gatchina town (near St. Petersburg) by Antonio Rinaldi for Count Grigori Grigoryevich Orlov who was a favourite of Catherine II. The Gatchina Palace is located on the hill above Lake Serebryannoe.
Antonio Rinaldi