Paul I of Russia
Paul remained overshadowed by his mother for most of his life. His reign lasted four years, ending with his assassination by conspirators. He adopted the laws of succession to the Russian throne—rules that lasted until the end of the Romanov dynasty and of the Russian Empire. He also intervened in the French Revolutionary Wars and, toward the end of his reign, added Kartli and Kakheti in Eastern Georgia into the empire which was confirmed by his son and successor Alexander I.
Paul I of Russia
He was "de facto" Grand Master of the Order of Hospitallers from 1799 to 1801, and ordered the construction of a number of Maltese thrones.