Placing the Great Vowel Shift between Chaucer and Shakespeare

When did the significant vowel change in English take place?

The rough marker offered is between Chaucer and Shakespeare, with no precise dates given.

A changing family-name spelling raises the question of when the major vowel change in English occurred. Chaucer and Shakespeare provide the rough chronological markers offered in reply. The comparison is a memory aid for changes in how older English sounds, rather than a precise start and finish date. Malory's later medieval writing supplies another context for reading older texts, including his participation in the Wars of the Roses and his writing in prison.