Answer:
During the reign of Alfred the Great
Step-by-step explanation:
With the unification of the Anglo-Saxon kingdoms by Alfred the Great in the later ninth century, the language of government and writing wound up institutionalized around the West Saxon vernacular (Early West Saxon).
Alfred upheld education in English alongside Latin, and had numerous works converted into the English language; some of them, for example, Pope Gregory I's treatise Pastoral Care, seem to have been interpreted by Alfred himself. In Old English, commonplace of the advancement of writing, verse emerged before exposition, yet King Alfred the Great essentially inspired the growth of prose.