Simplify the following text for a Grade 6 native English-speaking person.
Original: MÃ xima met the heir to the Dutch throne in April 1999 in Sevilla , Spain , during the Seville Spring Fair , also known as the `` Feria de abril de Sevilla . ''
Simplified: MÃ xima met the crown prince in April 1999 in Sevilla , Spain , during the Seville Spring Fair .