Shakespeare's Much Ado About Nothing (1598-1599) references the kingdom of Prester John in the following lines:
 

Benedick:

Will your grace command me any service to the world's end?
I will go on the slightest errand now
to the Antipodes that you can devise to send me on:
I will fetch a tooth-picker now from the
furthest inch of Asia: bring you the length of
Prester John's foot, fetch you a hair off the great
Cham's beard, do you any embassage to the Pigmies,
rather than hold three words' conference with this
harpy. You have no employment for me?

(Much Ado About Nothing 2.1.259-63)