I have an Elizabeth Messner, b. 1 March 1786, d. 1 Feb 1858; d/o Johannes & Catharina Messner.Elizabeth married James (Jacobus) Novinger (1779-1837) before 1804.One of their children was named Sarah.Both died in Killinger, Dauphin County, PA. They were my 3rd great grandparents. Many coincidences here, except for your "ca. 1800" marriage date. Regret no info on Johannes Messner.