Lord Govindaraja is the God of the place Tirupathi. Venkateswara came to Tirupathi lately. If there are two Vishnu temples in one place, the one who was established first will be called as elder brother of the one who came lately. That's how govindaraja become elder brother of venkateswara. This is followed in many places like, in Kanchipuram Lord varadharajaVaradharaja is known to be younger brother of Lord Yathokthakari perumal as varadharaja came after Yathokthakari perumal. Lord govindaraja was called by devas to be the witness for the agreement that Lord venkateswara's loan with kubera. Lord govindaraja verified all the money and jewels that was lent to Lord venkateswara. The amount was so huge that he became tired by that task so he lied there by making thr measuring jar as his pillow.