Who's death stopped His Imperial Majesty's Own Chancellery?
His Imperial Majesty's Own Chancellery:  канцелярия ) began as personal chancery of Pavel I and grew into a kind of regent's office, run by Count Arakcheyev from 1815 and until the death of Alexander I of Russia. Alexander I of Russia:  Alexander was the first Russian King of Poland, reigning from 1815 to 1825, as well as the first Russian Grand Duke of Finland.
Alexander I of Russia