Indo-Parthian coins generally closely follow Greek numismatics, they never display the Buddhist triratna symbol (apart from the later Sases), nor do they ever use depictions of the elephant or the bull, possible religious symbols which were profusely used by their predecessors. They are thought to have retained Zoroastrianism, being of Iranian extraction themselves. This Iranian mythological system was inherited from them by the later Kushans who ruled from the Peshawar-Khyber-Pakhtunkhwa region of Pakistan. Coins of the Hindu deity Shiva have also been found issued in the reign of Gondophares I. Representation of Indo-Parthian devotees On their coins and in the art of Gandhara, Indo-Parthians are depicted with short crossover jackets and large baggy trousers, possibly supplemented by chap-like over-trousers. Their jackets are adorned with rows of decorative rings or medals. Their hair is usually bushy and contained with a headband, a practise largely adopted by the Parthians from the 1st century AD. Individuals in Indo-Parthian attire are sometimes shown as actors in Buddhist devotional scenes. It is usually considered that most of the excavations that were done at Sirkap near Taxila by John Marshall relate to Indo-Parthian layers, although more recent scholarship sometimes relates them to the Indo-Greeks instead. These archaeological researches provided a quantity of Hellenistic artifacts combined with elements of Buddhist worship (stupas). Some other temples, such as nearby Jandial may have been used as a Zoroastrian fire temple. Buddhist sculptures The statues found at Sirkap in the late Scythian to Parthian level (level 2, 1–60 AD) suggest an already developed state of Gandharan art at the time or even before Parthian rule. A multiplicity of statues, ranging from Hellenistic gods, to various Gandharan lay devotees, are combined with what are thought as some of the early representations of the Buddha and Bodhisattvas. Today, it is still unclear when the Greco-Buddhist art of Gandhara exactly emerged, but the findings in Sirkap do indicate that this art was already highly developed before the advent of the Kushans. Stone palettes Numerous stone palettes found in Gandhara are considered as good representatives of Indo-Parthian art. These palettes combine Greek and Persian influences, together with a frontality in representations which is considered as characteristic of Parthian art. Such palettes have only been found in archaeological layers corresponding to Indo-Greek, Indo-Scythian and Indo-Parthian rule, and are essentially unknown the preceding Mauryan layers or the succeeding Kushan layers. Very often these palettes represent people