In Hinduism Lord Venkateswara is the Supreme God also another form of Lord Vishnu.  In this KaliYuga people are attached themself to material pleasures and forgot the diveness and so yogies praied Lord Vishnu ,should appear in Kaliyug to destroy the sins of the people,and develop self-realization, so he incarnated as Lord Venkateswarsa (which means Supre God destroys all the sins) from his devotees wishes. The other names for Venkateswara are Srinivasa, Venkatachalapathi, Balaji, Narayana,  Narayanadhri , Tirupathi Timmappa also. The Lord Venkateswara is appeared to be on seven hills(Venkata Hills) which is now populared as Tirumala near Tirupathi. That’s why he is also refered as “Yedukondala Venkateswara” (Seven hills recieted God) also by his disciples. Padmavathi is at her foot down called as Tiruchanur (Tirupathi)
Incarnation as Venkateswara :
In Purnas it is said to be the lord Vishnu came to this place in search of his abode lakshmi, as lakshmi left Vaikunta when a Bhrugu Maharshi came to visit and didn’t get the hounour, fractuated bhrugu kicked Lord Vishnu with his feet on his chest  a place where Sri Mahalaksmi resits, even by this also Vishnu is silent and so by anger Lakshmi devi left Vaikunta and later some time Maha Vishnu came to venkata hill in search of lakshmi, and after some month vishnu is surronded by ant-hill pity Bramha and maha shiva formed as cow and emptyed milk everyday which is belonged to Chola king and when cowherd shoot with his bow vishnu injured on forehead he saw vishnu blood he fell down and died, later  chola king found this and cursed by Vishnu which will end when he marries Padmavathi, Later Vishnu decided a stay on a hil of Varaha by which Vishnu blessed him, in future this place will be famous as Varaha Kshetram and he wil first  get prays and Naiyvedyam by every devotee who visits. Later one day Maha Vishnu heared a song which brought him to Vakiladevi . Both came to know their past, as Vakuladeva is re-birth of Yasodha who brought-up krishna, but unable to see his marriage, sho krishna that Dwapara Yug has promised her , that she will see his son’s marriage in next-birth, so Vakula devi treated Srinivasa as his son, and later Srinivasa meets princess Alamelu(Padmavathi) and soon fall in love, and his father agress and says that marriage should be performed grandly, for which Srinivasa abtained heavy loan from Kubera ( lord of wealth) and promises him that he will pay the debt with interest by end of kaliyuga.
 After marriage Srinivasa and Padmavathi where on the Varaha hill, then lakshmi see Vishnu and both quarrels saying that Srinivasa is her husband Vishnu, and by this Srinivasa becomes statue followed Padmavathi and Lakshmi statue also, which is prominet as the Swayambu of Lord Vishnu.