The Collaborative International Dictionary of English v.0.48:

Acquiet \Ac*qui"et\, v. t. [LL. acquietare; L. ad + quies rest.
   See Quiet and cf. Acquit.]
   To quiet. [Obs.]
   [1913 Webster]

         Acquiet his mind from stirring you against your own
         peace. --Sir A. Sherley.
   [1913 Webster]