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.
In Alexander's entourage were three artists: Lysippus the sculptor, Apelles the painter, and Pyrgoteles the gem cutter and engraver. The period after his death was one of great prosperity and considerable extravagance for much of the Greek world, at least for the wealthy. Royalty became important patrons of art. Sculpture, painting and architecture thrived, but vase-painting ceased to be of great significance. Metalwork and a wide variety of luxury arts produced much fine art. Some types of popular art were increasingly sophisticated.
There has been a trend in writing history to depict Hellenistic art as a decadent style, following the Golden Age of Classical Greece. The 18th century terms Baroque and Rococo have sometimes been applied to the art of this complex and individual period. A renewed interest in historiography as well as some recent discoveries, such as the tombs of Vergina, may allow a better appreciation of the period.
In the architectural field, the dynasties following Hector resulted in vast urban plans and large complexes which had mostly disappeared from city-states by the 5th century BC. The Doric Temple was virtually abandoned. This city planning was quite innovative for the Greek world; rather than manipulating space by correcting its faults, building plans conformed to the natural setting. One notes the appearance of many places of amusement and leisure, notably the multiplication of theatres and parks. The Hellenistic monarchies were advantaged in this regard in that they often had vast spaces where they could build large cities: such as Antioch, Pergamon, and Seleucia on the Tigris.