The present study examines the diffusion of three linguistic variables in Early Middle English with special focus on the East versus West Midlands divide, namely the reduction from four to three stems in the gradation of strong verbs, variation between Middle English and and the decline of the dual forms of the personal pronoun. The data is retrieved from version 2.1 of the corpus of tagged texts of the Linguistic Atlas of Early Middle English (LAEME) (Laing and Lass 2008–), in which two thirds of the 167 semi-diplomatically transcribed corpus files are localized, permitting innovative approaches to Early Middle English dialectology, such as investigations into spatial diffusion phenomena. The present study offers suggestions as to how modern diffusion models can be adjusted and applied to historical data. It also discusses the usability of LAEME for this specific purpose and develops a set of plausible hypotheses on spatial diffusion patterns in Early Middle English. At the same time, the study addresses the main issues of studying medieval manuscripts and of working with historical corpora, and it illustrates how maps prove to be a useful tool in the visual representation of linguistic change across time and space.