The Collaborative International Dictionary of English v.0.48:

Whomsoever \Whom`so*ev"er\, pron.
   The objective of whosoever. See Whosoever.
   [1913 Webster]

         The Most High ruleth in the kingdow of men, and giveth
         it to whomsoever he will.                --Dan. iv. 17.
   [1913 Webster]