Stowe provides further details about her story based on actual events in A Key to Uncle Tom’s Cabin.
To Stowe, Miss Ophelia represented a class of New Englanders who knew life without slavery, but could not move beyond the separation of races into two different castes. Stowe writes, “…although slavery has been abolished in the New England states, it has left behind it the most baneful feature of the system–that which makes American worse than Roman slavery–the prejudice of caste and colour.” (pg. 53)
Miss Opehlia has this sense of inequality and separation even though she is from the North and has not grown up around the institution of slavery.
The full story of this connection can be read in Chapter VII, “Miss Ophelia” of A Key to Uncle Tom’s Cabin.