If Rebecca is the female of age between 20 and 30 in the 1840 census, then her birth year is 1810-1820. Year 1810 makes her age about 16 at marriage.
Notes
Caution: Birth date is a complete guess based on date of marriage.
There are Knowles grandchildren listed in the will of father Reuben Ransom, probated in 1832, but Rebecca is not listed as a child. She may have died before 1832.[1]
The 11 Oct 1832, Clarke Co., GA, will of Reuben Ransom names "son in law Isaac Knowles; my grand children, Thomas, Reuben, Elizabeth, William, Sally and Mary Knowles." [2] The will does not name his daughter who was the wife of Isaac Knowles. Since this Rebecca (Ransom) Knowles is linked as the wife of Britton C. Knowles and her children are shown as Tabitha Knowles, Mary Jane (Knowles) Wilkins, and Frances R. (Knowles) Watson - none of whom are named in the will of Reuben Ransom of Clarke Co., GA, I've detached this Rebecca as a daughter of Reuben Ransom
Sources
↑Reuben Ransom in the Georgia, Wills and Probate Records, 1742-1992. Georgia. Court of Ordinary (Clarke County); Probate Place: Clarke, Georgia. Ancestry.com. Georgia, Wills and Probate Records, 1742-1992 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2015. Citing: Georgia County, District and Probate Courts. Accessed: 29 September 2018.
"Georgia, County Marriages, 1785-1950," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KXJZ-G8L : 17 October 2017), Brittain C. Knowles and Rebeccah Ransom, 12 Aug 1826; citing Marriage, Greene, Georgia, United States, county courthouses, Georgia; FHL microfilm 159,052.
"United States Census, 1840," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XHBZ-FR2 : 15 August 2017), Briton C Knowles, District 104, Hancock, Georgia, United States; citing p. 213, NARA microfilm publication M704, (Washington D.C.: National Archives and Records Administration, n.d.), roll 43; FHL microfilm 7,044.
Is Rebecca your ancestor? Please don't go away! Login to collaborate or comment, or ask our community of genealogists a question.