Simplify the following text for a Grade 10 native English-speaking person.
Original: After the 1866 Austro-Prussian War , the Kingdom of Hanover ( including the former bishopric of OsnabrÃ 1\/4 ck ) was annexed by Prussia .
Simplified: When the clerical states of Germany were dissolved , OsnabrÃ 1\/4 ck became part of the Kingdom of Hanover , which in turn fell to Prussia in 1866 .