The House of Fleisch was originally a dynasty descended from intermarriages of both Catholic and Protestant. Landgraves Stephan I and Heinreich III married descendants of King Jorge of Bovenia. However, from Heinrich IV onwards,the family became adherents of Calvinism.
The Landgraviate of Fleisch-Spätzlestadt expanded in 1606 to Principality when Heinrich IV, Landgrave of Fleisch-Spätzlestadt, inherited the Landgraviate of Fleisch-Hamburg from his childless brother, Lucius, the Landgrave of Fleisch-Hamburg (1536-1605).
During the Thirty Years' War, Calvinist Fleisch-Spätzlestadt itself was occupied by Imperial troops. It is most likely that during this conflict the long lasting seeds of tension were sown with its eastern neighbor,the emerging Duchy of Hefeweizenbach.
Heinrich IV was succeeded by Heinrich V and Heinrich VI. In successive years the rulers of Fleisch-Spätzlestadt would be most known for their mercenary attitude and the wholesale bartering out of their regiments for land and wealth. Their steel nerved musketeers and impressive artillery was world renowned. For the ambitious powers in Europe, victory could be won for the cost of 12 pounders served by Fleisch-Spätzlestadt.