Simplify the following text for a Grade 6 native English-speaking person.
Original: The Palio di Siena is a traditional medieval horse race run around the Piazza del Campo twice each year , on 2 July and 16 August .
Simplified: July 2 and August 16 are the dates when the Palio di Siena is held . The Palio is a traditional medieval horse race is run around the Piazza del Campo each year .