Simplify the following text for a Grade 10 native English-speaking person.
Original: Anastasia was a younger sister of Grand Duchess Olga , Grand Duchess Tatiana and Grand Duchess Maria , and was an elder sister of Alexei Nikolaevich , Tsarevich of Russia .
Simplified: She was a sister of Grand Duchess Olga , Grand Duchess Tatiana , Grand Duchess Maria , and Alexei Nikolaevich , Tsarevich of Russia .