In Hindu literature, one of the earliest mention of deity Brahma with Vishnu and Shiva is in the fifth Prapathaka (lesson) of the Maitrayaniya Upanishad, probably composed in late 1st millennium BCE, after the rise of Buddhism. The spiritual concept of Brahman is far older, and some scholars suggest deity Brahma may have emerged as a personal conception and icon with attributes (saguna version) of the impersonal universal principle called Brahman. The Buddhists attacked the concept of Brahma, states Gananath Obeyesekere, and thereby polemically attacked the Vedic and Upanishadic concept of gender neutral, abstract metaphysical Brahman. This critique of Brahma in early Buddhist texts aim at ridiculing the Vedas, but the same texts simultaneously call metta (loving-kindness, compassion) as the state of union with Brahma. The early Buddhist approach to Brahma was to reject any creator aspect, while retaining the Brahmavihara aspects of Brahma, in the Buddhist value system. Deity Brahma is also found in the samsara doctrine and cosmology of early Buddhism.