The Collaborative International Dictionary of English v.0.48:

Imperiality \Im*pe`ri*al"i*ty\, n.; pl. Imperialities.
   [1913 Webster]
   1. Imperial power.
      [1913 Webster]

   2. An imperial right or privilegs. See Royalty.
      [1913 Webster]

            The late empress having, by ukases of grace,
            relinquished her imperialities on the private mines,
            viz., the tenths of the copper, iron, silver and
            gold.                                 --W. Tooke.
      [1913 Webster]