One of most important sculptors working in bronze in the 400s B.C., Polykleitos, along with Pheidias, created the Classical Greek style. Although none of his original statues survive, literary sources and Roman marble copies of his work allow us to reconstruct the appearance of his works. An essential element of this style is the use of a relaxed and balanced pose, known today as contrapposto, which was the source of Polykleitos' fame. Polykleitos was most famous for statues of gods and athletes cast in bronze, but he also created a huge gold and ivory cult statue of the goddess Hera for the city of Argos.
Polykleitos consciously created a new approach to sculpture and even wrote a book setting out his aesthetic theories, the first ever by a sculptor. The book, called the Kanon, has not survived, but references to it in other ancient books imply that its main principle was expressed by the Greek words symmetria and rhythmos. By this Polykleitos meant that a statue should be composed of clearly definable parts, all related to one another through a system of ideal mathematical proportions and balance. The sources also say that Polykleitos cast a statue to demonstrate the principles of his Kanon. Polykleitos was the first sculptor known to have had a school of followers. The school of Polykleitos lasted for at least three generations, but it seems to have been most active in the late 300s and early 200s B.C. The Roman writers Pliny and Pausanias listed the names of about twenty sculptors of this school. The defining feature of their work was their adherence to the principles of balance and definition set out by Polykleitos.