Macbeth a tragedy

I have ruminated my Holinshed      
not idleheaded as in fairyland,      
but stern employment and in fullhearted      
hobnob with the past to put to my hand      
     
a play, master Holinshed, obliged me.    
And a right cruelhearted play at that,      
to sharp out-herod's killing roguery      
a Scott's King's murder an', all that, begat....      
     
I shall out, out, pen's honey-tongued humour      
to metamorphize to foul bloodyness,      
to silence my groundling's jaded clangour      
and turn rivals to green-eyed-monsterness.      
     
Such a wealth of murderous death within      
And witches, methinks, twill please that Scott's king.