Simplify the following text for a Grade 8 native English-speaking person.
Original: During the Napoleonic Wars , the earl 's art collection was inherited by the Wittelsbach family and moved to Munich , prompting the Prussian governmentâ '' who had annexed the DÃ 1\/4 sseldorf region after Napoleon had surrenderedâ '' to change it into a Royal Arts Academy in DÃ 1\/4 sseldorf , in 1819 .
Simplified: In time of the Napoleonic Wars it moved to Munich . So the government of Prussia , who annexed the region of DÃ 1\/4 sseldorf after Napoleon surrendered , to open a new Royal Arts Academy in DÃ 1\/4 sseldorf .