Complex sentence: Countess Alexandra Gallitzin (1774-1842) was a Maid of Honor and historian of the Russian noble family, Protasov and grandmother of the Roman Catholic missionary, Demetrius Augustine Gallitzin.
Split into simpler sentences: Countess Alexandra Gallitzin (1774-1842) was a Maid of Honor and Historian of the Russian noble family, Protasov. Alexandra was also the Grandmother of a Roman Catholic missionary, Demetrius Augustine Gallitzin.