The subject and adjacency effects found to condition the distribution of present verbal morphology in northern Middle English, and commonly referred to as the Northern Subject Rule (NSR), are generally regarded to be an Early Middle English development that did not condition the distribution of verbal morphology in northern varieties of Old English (Isaac 2003; Pietsch 2005; de Haas 2008; de Haas & van Kemenade 2015). Using data taken from the tenth-century interlinear gloss to the Lindisfarne Gospels, this study considers variation between the present-tense markers -ð and -s in Late Old Northumbrian and discusses evidence which indicates that the subject and adjacency effects at the crux of the NSR were already operative in Old Northumbrian with different morphological material. The findings also debunk the traditional conviction that -s spread first to second-person plural contexts and only subsequently to the third-person plural and singular (Holmqvist 1922; Blakeley 1949/50; Stein 1986).
