Complex sentence: The Battle of Bergen on April 13,1759 saw the French army under the de Broglie withstand an allied British, Hanoverian, Hessian, Brunswick army under Prince Ferdinand of Brunswick near Frankfurt-am-Main during the Seven Years' War.
Split into simpler sentences: The Battle of Bergen saw the French army under the de Broglie withstand an allied army consisting of British, Hanoverian, Hessian, and Brunswick troops commanded by Prince Ferdinand of Brunswick. It was fought on April 13,1759 near Frankfurt-am-Main during the Seven Years' War.