The similarities between the iconography and theologies of Shiva with Greek and European deities have led to proposals for an Indo-European link for Shiva, or lateral exchanges with ancient central Asian cultures. His contrasting aspects such as being terrifying or blissful depending on the situation, are similar to those of the Greek god Dionysus, as are their iconic associations with bull, snakes, anger, bravery, dancing and carefree life. The ancient Greek texts of the time of Alexander the Great call Shiva as "Indian Dionysus", or alternatively call Dionysus as ""god of the Orient"". Similarly, the use of phallic symbol as an icon for Shiva is also found for Irish, Nordic, Greek (Dionysus) and Roman deities, as was the idea of this aniconic column linking heaven and earth among early Indo-Aryans, states Roger Woodward. Others contest such proposals, and suggest Shiva to have emerged from indigenous pre-Aryan tribal origins.