While it’s true that Shakespeare used the phrase in his famous play, Hamlet, he didn’t make the phrase up as he did so many other phrases that are part of every day English these days.
A published version of the concept of seeing something in “my mind’s eye” can be found in a letter written by Hubert Languet to Sir Philip Sidney in 1577. In his letter he wrote:
“What will not these golden mountains effect … which I dare say stand before your mind’s eye day and night?“
However, the concept of “my mind’s eye” was used by Chaucer in The Man of Law’s Tale, written in 1390, where he wrote:
“It were with thilke eyen of his mynde, With whiche men seen, after that they been blynde.“
But even before then, in 1183, a Christian mystic by the name of Joachim of Flora wrote “Exposition of Revelation” in which the reader can find this passage:
“I suddenly perceived in my mind’s eye something of the fullness of this book and of the entire harmony of the Old and New Testaments.”
And so we see that even though Shakespeare made good use of the phrase, since at least the late 1100s, the words mind and eye have been paired in the sense of “a mental view.”
Historically Speaking 