The cinema of Iran (Persian: سینمای ایران), or of Persia, refers to the film industries in Iran and their productions. Iranian art films have garnered international fame and enjoy a global following. Iranian films are usually written and spoken in the Persian language. Iran has been lauded as one of the best exporters of cinema in the 1990s. Some critics now rank Iran as the world's most important national cinema, artistically, with a significance that invites comparison to Italian neorealism and similar movements in past decades. A range of international film festivals have honoured Iranian cinema in the last twenty years. Many film critics from around the world have praised Iranian cinema as one of the world's most important artistic cinemas. Persian theatre The earliest examples of visual representations in Iranian history may be traced back to the bas-reliefs in Persepolis (c. 500 BC). Bas relief is a method of sculpting which entails carving or etching away the surface of a flat piece of stone or metal. Persepolis was the ritual center of the ancient kingdom of Achaemenids and "the figures at Persepolis remain bound by the rules of grammar and syntax of visual language." Iranian visual arts may be said to have peaked about a thousand years later during the Sassanian reign. A bas-relief from this period in Taq Bostan (western Iran) depicts a complex hunting scene. Similar works from the period have been found to articulate movements and actions in a highly sophisticated manner. It is even possible to see the progenitor of the cinema close-up: a wounded wild pig escaping from the hunting ground, among these works of art. After the conversion from Zoroastrianism to Islam; Persian art continued its visual practices. Persian miniatures provide great examples of such continued attempts. The deliberate lack of perspective in Persian miniature enabled the artist to have different plots and sub-plots within the same image space. A very popular form of such art was Pardeh Khani. Another type of art in the same category was Naqqali.