Simplify the following text for a Grade 8 native English-speaking person.
Original: She was born Princess Jelena of Serbia , and was known as Elena Petrovna , Jelena Petrovna , HÃ lÃ ne Petrovna or Ellen Petrovna after her marriage .
Simplified: After she was married , she was known as Elena Petrovna , Jelena Petrovna , HÃ lÃ ne Petrovna or Ellen Petrovna .