<human>:  What is the history of ballet?
<bot>: The history of ballet dates back to the 15th century in the Italian Renaissance courts of the Medici and Estes families. It quickly spread to France, England and Russia, and was popularized in the theatrical courts of the 17th and 18th centuries. In the 19th century, ballet changed dramatically, with the emergence of choreographers like Marius Petipa, who created popular ballets like Swan Lake, The Nutcracker, and La Bayadere. In the 20th century, ballet continued to grow and evolve, with the advent of neoclassical and contemporary ballet styles. Today, ballet is enjoyed all over the world, from traditional performances to innovative works that push the boundaries of the art form.