This brief history of kissing (now why didn’t I think of that for a dissertation subject?) in the
London Times is a kind of interesting. But it is a bit prosaic. But not so when Paulo and Francesca kissed. Dante has Francesca say that they had been alone and without fear, reading, and then at one point they were overcome and then he "Kissed me upon the mouth all palpitating...That day no farther did we read therein." See this.
And there were consequences.