Classicism was a cultural movement that was part of the European Renaissance during the 15th and 16th centuries. As its name implies, the proposal of Classicism was a return to the forms and themes of Classical Antiquity, ie ancient Greece and Rome.
The cultural horizon of the Renaissance was Classical Antiquity. Ancient Greece is considered the cradle of Western thought (having directly influenced Roman culture), so the return to classical forms was the aesthetic purpose of the Renaissance. Classicism has its genesis in Italy, at the end of the thirteenth century, with the emergence of humanist thinking.
Today's ballet dancers will know many of the names of the steps, but the style of performing the steps today is different from the Baroque era, for example, in classical ballet the emphasis is up (high on the toes), while the Baroque style is more rooted to the ground (the heels just off the floor). so the baroque period was more natural and relaxed
