Family #71 in the 1834 Grimm census.
Family #75 in the 1857 Grimm census.
Apollonia, last name at birth unknown, was born in 1813 in Grimm, Russia. She married Johannes Wittmann before 1831. The couple had three children:
Christian Jakob Wittmann, born 1832
Louisa Charlotta Wittmann, born 1834
Katharlina Elisabeth Wittmann, born 1839
Elisabeth Wittmann, born 1841
It's possible they had additional daughters born between 1835 and 1840 who were married and living with their husbands' families by 1857. In these cases, these females would never have been documented in a Russian census with their biological parents.
Apollonia was born after the 1798 census and married before the 1834 census. This means she was not captured in a census with her biological parents. Unless we find a descendant who has detailed private records, we will probably never know her last name at birth.
Studying the maternal haplogroup of Apollonia's female descendants could help narrow down her maternal ancestry.
Child #1 Christian Jakob Wittmann, age 24 years 6 months
Child #2 Katharina Elisabeth Wittmann, age 18
Child #3 Elisabeth Wittmann, age 16
Brother #1 Konrad Wittmann, age 42 in 1850, to Rosenberg in 1852
Child #4 Valentin Wittmann, age 21 in 1850, to Rosenberg in 1852
Child #5 Michael Wittmann, age 19 in 1850, to Rosenberg in 1852
Child #6 Johann Georg Wittmann, age 17 in 1850, to Rosenberg in 1852
Child #7 Johann Friedrich Wittmann, age 3 in 1850, to Rosenberg in 1852
Brother #2 Unnamed Wittmann, probably Johann Michael Wittmann, probably deceased before 1850 and his death noted in that male-only census
Child #8 Georg Heinrich Wittmann, age 18, nephew by unnamed brother
Child #9 Johannes Wittmann, age 16, nephew by unnamed brother
Child #10 Heinrich Wittmann, age 14, nephew by unnamed brother
Child #11 Konrad Wittmann, age 12, nephew by unnamed brother
↑1834 Census of Grimm in the District of Saratov, Russia, dated 2 February 1835; Translated by Brent Mai, Concordia University, Portland, Oregon; Published by Dynasty Publishing, Beaverton, OR, USA; Published 2011; page 22-23, family #71, Martin Wittmann family.
↑1857 Census of Grimm in the District of Saratov, Russia, dated 5 November 1857; Translated by Brent Mai, Concordia University, Portland, Oregon; Published by Dynasty Publishing, Beaverton, OR, USA; Published 2005; page 30, family #75, Johann Wittmann family.