Maria Christina was born in 1808, 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 Maria Christina's female descendants could help narrow down her maternal ancestry.
Head of the Household Johann Jakob Schneider, age 60
Wife Maria Christina Schneider, age 50
Child #1 Johann Philipp Schneider, age 39
Wife of Child #1 Elisabeth Margaretha Schneider, age 34
Grandchild #1 Katharina Elisabeth Schneider, age 14
Grandchild #2 Anna Elisabeth Schneider, age 11
Grandchild #3 Christian Jakob Schneider, age 10
Grandchild #4 Maria Barbara Schneider, age 7
Grandchild #5 Karl Schneider, age 4
Grandchild #6 Katharina Schneider, age 1 year 6 months
Child #2 Nikolaus Schneider, age 27
Wife of Child #2 Helena Schneider, age 28
Grandchild #7 Katharina Elisabeth Schneider, age 5
Child #3 Louisa Schneider, age 24
Child #4 Johann Jakob Schneider, age 17
Maria Christina was Johann Jakob Schneider's second wife in the 1857 Grimm census. There are only two possible people from the 1834 census whom she could be:
Family #206 Maria Christina 1808 1st Husband: Tobias Eberhardt
Family #242 Maria Christina 1808 1st Husband: Jakob Alexander Schneider
Tobias Eberhardt was married to a different, much younger woman at the time of the 1857 census.
Usually this means that his first wife passed away, as divorce was uncommon in the Volga German community. This is not a likely match.
Jakob Alexander Schneider passed away in 1851 and his wife was no longer listed with his family in the 1857 census.
This could mean she remarried or passed away. His wife in the 1834 census was named Maria Christina and her age is a match with the Maria Christina of this profile. These two references to Maria Christina appear to refer to the same woman.
As of the 1834 Grimm census, Alexander and Maria Christina had three children:
Anna Katharina, born 1827
Johannes, born 1829
Katharina Elisabeth, born 1832
In the 1857 census which shows the death of Alexander Schneider and no wife, there are five children listed:
Charlotta, born 1838
Christina, born 1841
Margaretha, born 1844
Georg Konrad, born 1845
Johann Jakob, born, 1848, deceased 1851
None of the birth years overlap with the children listed in the Johann Jakob Schneider household in 1857, a fact that helps support that she was the mother of all Alexander Schneider's 8 children, 3 from the 1834 census and 5 in the 1857 census.
Her three oldest children were old enough to be married and living in other households. With her youngest child born in 1848, she could not have married Johann Jakob Schneider until after that year.
Since we know her first husband Alexander Schneider died in 1851, she must have remarried to Johann Jakob Schneider after Alexander's death, perhaps as early as 1851 or 1852.
In the 1857 census listing for Maria Christina in the Johann Jakob Schneider household, the oldest child was 39 years old compared to her 50 years of age.
Since it would be highly unusual to give birth at the age of 11, she cannot be that child's biological mother. Most likely she was not the mother of any of Johann Jakob Schneider's children. If she married Johann Jakob Schneider in 1851-1852, the oldest any child of theirs could be was 6 years of age. That does not match the age of any child in the family. It appears that she and Johann Jakob Schneider had no children together, at least none before 1857. Maria Christina was 49 years old that year, and the likelihood that the couple had children when she was aged 50 or older are slim.
One final note: Although her two husbands shared the surname Schneider, they were not from the same family line, therefore not related. It may be that some of their descendants are related through a later marriage, but as of 1857, there was no biological connection between these two family lines.
↑ 1.01.11.21.31834 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 100, family #270, lines 4324 through 4329, Alexander Schneider, Charlotta, Christina, Margaretha, Georg Konrad and Johann Jakob Schneider, her deceased husband and biological children.
↑ 2.02.11857 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 73, family #194, Johann Jakob Schneider family.
↑ 3.03.11857 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 88, family #234, Tobias Eberhardt family.
↑ 4.04.14.24.31857 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 100, family #270, Johann Georg Schneider family; Alexander, deceased 1851, and children Charlotta, Christina, Margaretha, Johann Konrad and Johann Jakob.