Among the processes which have contributed to form Vishṇu and Śiva we must reckon the invasions which entered India from the north-west.[336] In Bactria and Sogdiana there met and were combined the art and religious ideas of Greece and Persia, and whatever elements were imported by the Yüeh-chih and other tribes who came from the Chinese frontier. The personalities of Vishṇu and Śiva need not be ascribed to foreign influence. The ruder invaders took kindly to the worship of Śiva, but there is no proof that they introduced it. But Persian and Græco-Bactrian influence favoured the creation of more definite deities, more personal and more pictorial. The gods of the Vedic hymns are vague and indistinct: the Supreme Being of the Upanishads altogether impersonal, but Mithra and Apollo, though divine in their majesty, are human in their persons and in the appeal they make to humanity. The influence of these foreign conceptions and especially of their representation in art is best seen in Indian Buddhism. Hinduism has not so ancient an artistic record and therefore the Græco-Bactrian influence on it is less obvious, for the sculpture of the Gupta period does not seem due to this inspiration. Neither in outward form nor in character do Vishṇu and Śiva show much more resemblance to Apollo and Mithra than to the Vedic gods. Their exuberant, fantastic shapes, their many heads and arms, are a symbol of their complex and multiple attributes. They are not restricted by the limits of personality but are great polymorphic forces, not to be indicated by the limits of one human shape.[337] 2