We study an instance of semantic change observed with the Latin particle quidem, which in essence is a common-ground managing particle indicating that a given piece of information is presupposed (approximate English translations include ‘indeed’, ‘certainly’, ‘in fact’ and ‘admittedly’). On the basis of corpus work on Early and Classical Latin texts, we show that the development of a use of quidem in combination with negation goes hand-in-hand with the development of a use in (counterexpectational) adversative contexts. We propose that the semantic-pragmatic link between the two innovative uses is the rhetorical over-use of the particle, which develops in two different ways. In the case of the complex negative particle ne…quidem, we propose that over-use detaches the particle from its basic common-ground managing function and turns it into a focus particle. In the case of the employ in adversative contexts, we propose that the same effect of over-use leads to the conventionalization of more local anaphoric-cataphoric relations.