Classicism is any attempt to emulate style and idea of ancient Greece or Rome. Neoclassicism is a label for this kind of art about 1800, mainly by Jacques-Louis David and his colleagues.
The Renaissance is the era beginning about the 15th century when new ideas began to emerge in Europe as a result of the proliferation of books as a result of Gutenberg's invention of a practical way...
The renaissance came a few hundred years after the medieval times also greater discoveries were made in the renaissance such as artists who drew non religious paintings.
The Renaissance was the spark of the coming technology and self expression, the Harlem Renaissance was that same spart but for the black community north and south, self expression and music...