The emergence of a secondary negator (na, later not) in the early history of English raises the question as to how such an element is integrated into the syntactic structure. Responding to work by van Kemenade (2011), this paper starts by providing evidence in support of her proposal that the secondary negator can occur in a high and in a low structural position in Old English. However, no conclusive evidence is found for the presence of a dedicated position for negation in the clause structure (NegP) at this stage of the history of English. As for the variation in the placement of the secondary negator, it is shown that, contrary to what van Kemenade proposes, low negation is not restricted to certain contexts but is available more generally. The restriction of high negation to V-to-C contexts is confirmed and an analysis of this restriction in terms of binary Agree relations is proposed. Finally, it is shown that this analysis is compatible with the diachronic developments occurring during the Middle English period.