Simplify the following text for a Grade 8 native English-speaking person.
Original: After over 30 years of Mori control , in 1600 Horio Yoshiharu enters Izumo and Oki as the result of Battle of Sekigahara which Mori lost .
Simplified: After over 30 years of Mori control , in 1600 Horio Yoshiharu entered Izumo and Oki after the Battle of Sekigahara which Mori lost .