Simplify the following text for a Grade 4 native English-speaking person.
Original: The Iron Cross was a military decoration of the Kingdom of Prussia , and later of Germany , which was established by King Friedrich Wilhelm III of Prussia and first awarded on 10 March 1813 in Breslau , during the Napoleonic Wars .
Simplified: The award was created by King Frederick William III of Prussia . It was first given out on 10 March 1813 .