She was the daughter of Tsar Paul who lived between 1784 and 1803. She married Friedrich Ludwig of Mecklenburg-Schwerin in 1799 and bore two children before dying suddenly. Among her great grandchildren are Grand Princess Elizaveta Mavrikievna, Grand Princess Maria Pavlovna the Elder, Franz Friedrich who married Anastasia Mikhailovna, and one generation further removed Crown Princess Cecilie and Queen Alexandrine of Denmark. Her Wikipedia article is here.
Charlotte of Württemberg would later travel to Russia to become Grand Princess Elena Pavlovna.