In Andhra Kaumudi, a Telugu grammar book it was mentioned that Āndhra Viṣhṇu having built an immense wall, connecting Sri Sailam, Bhimeswaram, and Kaleswaram, with the Mahendra hills, formed in it three gates, in which the three eyed Ishwara, bearing the trident in his hand and attended by a host of divinities resided in the form of three lingams. Āndhra Viṣhṇu assisted by divine angels having fought with the great giant Nishambhu for thirteen yugas killed him in battle and took up his residence with the sages on the banks of the river Godavari, since which time, the Telugu country has been named Trilingam.[2]