Hellenistic art is the art of the period in classical antiquity generally taken to begin with the death of Alexander the Great in 323 BC and end with the conquest of the Greek world by the Romans, a process well underway by 146 BC, when the Greek mainland was taken, and essentially ending in 31 BC with the conquest of Ptolemaic Egypt following the Battle of Actium. A number of the best-known works of Greek sculpture belong to this period, including Laocoön and His Sons, Venus de Milo, and the Winged Victory of Samothrace. It follows the period of Classical Greek art, while the succeeding Greco-Roman art was very largely a continuation of Hellenistic trends.
The term Hellenistic refers to the expansion of Greek influence and dissemination of its ideas following the death of Alexander – the "Hellenizing" of the world, with Koine Greek as a common language. The term is a modern invention; the Hellenistic World not only included a huge area covering the whole of the Aegean, rather than the Classical Greece focused on the Poleis of Athens and Sparta, but also a huge time range. In artistic terms this means that there is huge variety which is often put under the heading of "Hellenistic Art" for convenience.
One of the defining characteristics of the Hellenistic period was the division of Alexander's empire into smaller dynastic empires founded by the diadochi (Alexander's generals who became regents of different regions): the Ptolemies in Egypt, the Seleucids in Mesopotamia, Persia, and Syria, the Attalids in Pergamon, etc. Each of these dynasties practiced a royal patronage which differed from those of the city-states.