Complex sentence: The howitzer was mainly designed by Krupp's Director of design, Professor Fritz Rausenberger, and his predecessor, Director Dräger, and it was these designers who christened the weapon "Dicke Bertha" after Bertha Krupp, heiress and owner of the Krupp industrial empire.
Split into simpler sentences: The howitzer was mainly designed by Krupp's Director of design, Professor Fritz Rausenberger, and his predecessor, Director Dräger. It was these designers who christened the weapon "Dicke Bertha" after Bertha Krupp, heiress and owner of the Krupp industrial empire.