Simplify the following text for a Grade 6 native English-speaking person.
Original: Sophie 's constitutional position became difficult after Frederick 's death in 1588 , when she found herself in a power struggle with the Rigsraad for control of King Christian .
Simplified: Sophie 's position became harder after Frederick 's death in 1588 . She had to join in a power struggle with the Rigsraad for control of King Christian .