Simplify the following text for a Grade 7 native English-speaking person.
Original: The Greco-Persian Wars ( also often called the Persian Wars ) were a series of conflicts between the Achaemenid Empire of Persia and city-states of the Hellenic world that started in 499 BC and lasted until 449 BC .
Simplified: The Greco-Persian wars were a series of wars fought between Ancient Greece and Persia 's Achaemenid Empire in the 5th century BC . The struggle lasted 50 years , from 499 -- 449 .