Which historical form of English came between Old English and Early Modern English?

Middle English was the historical form of English between Old English and Early Modern English.

It developed after the Norman Conquest of 1066 and was spoken in England roughly until the late 15th century. The language changed substantially through contact with Anglo-Norman French and Old Norse, while many Old English inflectional endings gradually disappeared.

Middle English was not a single uniform dialect. Northern, Midlands, and Southern varieties differed in pronunciation, vocabulary, and grammar. Geoffrey Chaucer’s Canterbury Tales is among its best-known literary works, although Chaucer’s London-based language can still look very unfamiliar to modern readers.

Early Modern English emerged during the late 15th and 16th centuries. William Caxton’s printing press, the spread of London-based written standards, and later the Great Vowel Shift helped move English toward its modern form. Proto-English is an ancestor, not the intervening period; Classical English is not the standard name for any stage of English.