This paper presents two large datasets, one of over 19,000 morphemes from 100 texts, the other of over 91,000 spellings from 941 texts across 198 manuscripts for one phonological segment, with a view to providing an empirical basis for discussions of the homogeneity with which the vernacular was written in late Anglo‐Saxon England. These show the infinitive morpheme was spelt <‐an> 96.1 per cent of the time and the diphthong /æa, æ:a/ was written 96.5 per cent of the time. Such consistency, over time and across dialect boundaries, suggests that recent scepticism about the existence of a homogenous, conservative, supraregional variety of written Old English, perhaps a ‘standard’ Old English, is unwarranted.