The age of romanticism (late 1700's, early 1800's) came as a stark contrast to classicism. When you think of classicism, think of the beautiful, fine art of the middle ages and forward. This art imitated classic Greek and Roman art, which was thought to be the ideal. A good example is Michelangelo's Statue of David. Classical art was characterized by harmony, balance, and perfect proportion. Those who we now refer to as the romantics saw classical art as restraining, reserved, and unfavorable to individual freedom of expression. The romantic era featured artists who sought to express as much new creativity as possible, rather than model all their art after somebody else, as classicism did.
I hope this helps!