This study aims to provide both synchronic and diachronic accounts for NC in OE. Concerning the single negative relation in NC, the hypothesis is proposed that n-words in NC carry the [uNEG] feature which should be matched against the [iNEG] feature of the functional head Neg via the syntactic operation of Agree. Nevertheless, textual investigation reveals that the frequency of NC in OE radically differs depending on the period of authorship: its relative paucity in EOE and predominance in LOE. The emergence of NC in OE is associated with the diachronic reduction of the XP sentential negator into the X0 Neg, since only the X0 Neg takes the [iNEG] feature matching with the [uNEG] feature of n-words. Subsequently, the introduction of n-words can be understood as a solution to reinforce weakened sentential negation. Through the process of grammaticalization, one of those n-words becomes a second negator with the XP status, starting on its way to negative cycle.