Simplify the following text for a Grade 11 native English-speaking person.
Original: The 1964 Winter Olympics , officially known as the IX Olympic Winter Games , were a winter multi-sport event which was celebrated in Innsbruck , Austria , from January 29 to February 9 , 1964 .
Simplified: The 1964 Winter Olympics , officially known as the IX Olympic Winter Games , were celebrated in Innsbruck , Austria , from January 29 to February 9 , 1964 .