In a witness testimony from 1714, Ralph Coleman, a London butcher, relates the following dialogue that he overheard between the Reverend Robert Barry and Sarah Twycrosse (the here unnamed “Woman”), a hostel keeper.
… S∼ [‘Sir’] I want to speake with you, to wch [‘which’] the sd [‘said’] Robert Barry replyed, Madam, I have nothing to say to you wherto shee replyed, Sr I have something to say to you, & shall speake it in publick to wch the said Robert Barry replyed, Yes and Welcome & thereupon the said ∧﹛Woman﹜ answeared him, Why then Sr I will. The Woman that I saw in bed with you is now with Child (ETED: London 1714–1715: F_4LD_London_003)
We will leave aside whether Coleman accurately repeated what was originally said – we will have a closer look at the issue of textual reliability later. What is particularly interesting for us in this exchange is the way Twycrosse and Barry address each other. Twycrosse uses sir three times, and Barry responds once with madam. We can assume from modern conventions of address that this usage carried important social implications. After all, in modern contexts, the choice of address term (sir, ma'am, professor, Mr., Ms., Mrs., Ralph, Sarah, idiot, etc.) sends social signals about how we relate to (or perceive our relation to) the people we address: whether we see them as socially more or less powerful than ourselves, as socially close, etc. The selection may also reflect the particular situation we find ourselves in: whether formal or informal, or perhaps whether we feel happy or displeased with a person at a particular point. In the case of the early eighteenth-century exchange above, despite making quite a grave accusation against the clergyman, Twycrosse seems to politely acknowledge the social distance between them by using sir, a term normally used for a man of higher rank at the time. On the other hand, she may be emphasizing the distance between them (considering the behavior she is accusing him of). The repeated, insistent use of sir may even carry a hint of irony: you may be a sir, but your behavior certainly does not reflect that status (intonation patterns, which we unfortunately do not have access to, would have been helpful here).