The Aditya Hridayam is a hymn to Surya, the Sun, that makes up one whole chapter of the Yuddha Kanda in Sage Valmiki's Ramayana. Its thirty-one verses are set on the battlefield, where Sage Agastya, who has come with the gods to watch the battle, finds Rama weary and lost in thought as Ravana stands ready to fight. Its name means the heart of Aditya — the Sun as the son of Aditi.
Sage Agastya praises the rising Sun as the self of all the gods, naming him Brahma, Vishnu, Shiva and Skanda, and as the one who guards the worlds with his rays; a string of the Sun's names and salutations follows. He tells Rama to recite the hymn three times, and departs. Rama looks to the Sun, recites it, sips water three times and takes up his bow, and in the closing verse the Sun himself, from among the gods, tells him to make haste.
The Aditya Hridayam is among the prayers offered to Surya at Ratha Saptami, the Sun's festival in the month of Magha, and some Sun temples hold mass recitations of it that day. In this collection, Surya presides at Arasavalli and at Suryanar Kovil, while the temples at Konark and Modhera were aligned so that the rising sun would reach the sanctum.