Simplify the following text for a Grade 4 native English-speaking person.
Original: Lenzburg was conquered by Bern in 1415 , along with the western part of current Aargau , though Bern did not take away its city rights .
Simplified: Lenzburg was conquered by Bern in 1415 , along with the western part of what is now Aargau . Bern did not take away its city rights .