Introducing Shakespeare: A Graphic Guide - Nick Groom, Piero 2013
The Original or “Ur-Hamlet”
On the other hand, contemporary thinking is that Shakespeare adapted an earlier play, the “Ur-Hamlet”, played at least as early as 1594 and perhaps dating from the 1580s. The critic Harold Bloom argues persuasively that the Ur-Hamlet is in fact Shakespeare’s first, lost play, dating from 1588 and soon after adapted by Thomas Kyd as The Spanish Tragedy.
SHAKESPEARE REWROTE HAMLET ALMOST PERPETUALLY … I WAS ALSO WRITING OTHER THINGS TOO, OF COURSE.