The jyotirlingam was worshipped by Lord Rama to atone the sin of killing Ravana. Hanuman flew to bring the Linga from Kailasa, for Lord Rama to wroship. As it was getting late, Rama worshipped the Lingam that was made of sand by Sita Devi. This Lingam worshipped by Lord Rama is known as Ramanathar. When Hanuman returned he was disappointed that his Lord had not used the Lingam that he had brought. Lord Rama pacified Hanuman & named this Lingam Kasi Viswanathar. Devotees have to worship Kasi Viswanathar before worshipping Ramanathar.
Rameswaram is famous for the many teerthams. There are a total of 51 teerthams, 22 of them situated within the temple. Pilgrimage is considered complete with a bath in the Agni teertham. These waters are considered to have medicinal qualities.
It is the custom to worship at Dhanushkodi before going to Rameshwaram. Several spots in this island are associated with Lord Rama. The Kothandarama temple stands at the spot where Vibeeshanan sought refuge to Rama.