The Collaborative International Dictionary of English v.0.48:

Heretoch \Her"e*toch\, Heretog \Her"e*tog\, n. [AS. heretoga,
   heretoha; here army + te['o]n to draw, lead; akin to OS.
   heritogo, OHG. herizogo, G. herzog duke.] (AS. Antiq.)
   The leader or commander of an army; also, a marshal.
   --Blackstone.
   [1913 Webster]