What is the connection between marriage and social status in the three marriages in Jane Austen's Emma: the marriages of Jane Fairfax and Frank Churchill, Harriet and Robert Martin, Emma and Mr. Knightley?
The strangest connection between marriage partners and social status is in that between Jane Fairfax and Frank Churchill. Jane is the daughter of Miss Bates's sister, who was Mrs. Bates's younger daughter. The Bates were high enough in social status for Miss Bates's sister to marry a commissioned officer, "Lieut. Fairfax," in the regimental military. Indeed, Mr. Knightley refers to the lessened social status in which the Bates's now live, especially when he scolds Emma for being discourteous and unkind to Miss Bates, "She is poor; she has sunk from the comforts she was born to":
Jane Fairfax was an orphan, the only child of Mrs. Bates's youngest daughter.
The marriage of Lieut. Fairfax ... and Miss Jane Bates, had had its day of fame and pleasure, ... but nothing now remained of it, save the melancholy remembrance of him dying in action abroad—of his widow sinking under consumption and grief soon afterwards—and this girl.
Frank Churchill is the natural son of Mr. Weston whose family was "respectable" yet originally without property or wealth, though they had been rising in both for "two or three generations." Mr. Weston, receiving a small inheritance in his youth, advanced his position further by "entering into the militia of his county" and rising to Captain. Frank, after his father had left the militia and gone into trade and after the early death of his mother, was adopted by his Uncle and Aunt Churchill and raised in their family having high social status. Thus, this marriage was, in its natural circumstances, between a bride of a higher social status and a groom of a lower one, notwithstanding his adoptive circumstances elevated him into a higher social status.
The marriage between Robert Martin and Harriet is of no exceptional interest relating to social status: he is an established respectable farmer; she is a respectable well provided for, though independent, woman on the same socio-economic level. The one distinguishing factor here is that Harriet is the illegitimate--though well cared for and properly educated--daughter of a tradesman. Her unknown parentage (though it does become known) sets her off with a unique and distinct social status that would have barred anyone higher than Robert Martin from seriously considering a marriage with her, as Elton made quite clear. Nonetheless, had she not been illegitimate, as the daughter of a wealthy tradesman, she would have been more on the level of a Mr. Elton than a Farmer Martin (thus it turned out well for Martin!).
[Harriet] proved to be the daughter of a tradesman, rich enough to afford her the comfortable maintenance which had ever been hers, and decent enough to have always wished for concealment.
The marriage between Emma and Mr. Knightley is the least remarkable of all in terms of social status. He is a gentleman of wealth. She is the daughter of a gentleman of wealth. They are perfectly suited and equal in social status. The one peculiarity in their marriage is that Mr. Knightley agrees to leave Donwell Abbey--the dominant residence and seat of the primary patron of Highbury and the surrounding farms--and live with Emma in Mr. Woodhouse's house in order to care for him. Otherwise, it is socially perfectly ordinary and right that Emma and Mr. Knightley marry.