a bull as his vehicle, Nandi. The horns of Agni, who is sometimes characterized as a bull, are mentioned. In medieval sculpture, both Agni and the form of Shiva known as Bhairava have flaming hair as a special feature. Indra According to Wendy Doniger, the Saivite fertility myths and some of the phallic characteristics of Shiva are inherited from Indra. Doniger gives several reasons for her hypothesis. Both are associated with mountains, rivers, male fertility, fierceness, fearlessness, warfare, the transgression of established mores, the Aum sound, the Supreme Self. In the Rig Veda the term is used to refer to Indra. (2.20.3, 6.45.17, and 8.93.3.) Indra, like Shiva, is likened to a bull. In the Rig Veda, Rudra is the father of the Maruts, but he is never associated with their warlike exploits as is Indra. Indra himself may have been adopted by the Vedic Aryans from the Bactria–Margiana Culture. According to Anthony, The texts and artwork of Jainism show Indra as a dancer, although not identical generally resembling the dancing Shiva artwork found in Hinduism, particularly in their respective mudras. For example, in the Jain caves at Ellora, extensive carvings show dancing Indra next to the images of Tirthankaras in a manner similar to Shiva Nataraja. The similarities in the dance iconography suggests that there may be a link between ancient Indra and Shiva. Development A few texts such as Atharvashiras Upanishad mention Rudra, and assert all gods are Rudra, everyone and everything is Rudra, and Rudra is the principle found in all things, their highest goal, the innermost essence of all reality that is visible or invisible. The Kaivalya Upanishad similarly, states Paul Deussen – a German Indologist and professor of philosophy, describes the self-realized man as who "feels himself only as the one divine essence that lives in all", who feels identity of his and everyone's consciousness with Shiva (highest Atman), who has found this highest Atman within, in the depths of his heart. Rudra's evolution from a minor Vedic deity to a supreme being is first evidenced in the Shvetashvatara Upanishad (400–200 BCE), according to Gavin Flood, presenting the earliest seeds of theistic devotion to Rudra-Shiva. Here Rudra-Shiva is identified as the creator of the cosmos and liberator of Selfs from the birth-rebirth cycle. The Svetasvatara Upanishad set the tone for early Shaivite thought, especially in chapter 3 verse 2 where Shiva is equated with Brahman: