It is said that Rama installed the Siva-linga in the Ramananthaswami Temple on his return to the mainland from the island of Lanka, after killing Ravana. Rama wanted to install a Siva-linga in Rameswaram to absolve himself of the sin of killing Ravana, who was a Brahmin. Rama sent Hanuman to Mount Kailash to get the linga. Hanuman was late, so when the auspicious time for the installation neared, Sita made a Siva-linga out of sand. This linga was then installed by Rama and is known as the Rama-linga, because Lord Rama installed it.
At that time Hanuman came with the Siva-linga from Kailash. He was disappointed to find a linga already installed. Rama told Hanuman that he could remove the linga made by Sita and install the one that he brought in its place. Hanuman took hold of the linga with his hands and could not move it. He then wrapped his tail around it and tried to pull the linga out, but it did not move. The linga is said to still have the marks of Hanuman’s tail on it. To pacify Hanuman, Rama had the linga that he brought, the Viswa-linga, installed alongside the Rama-linga. He ordered that puja (worship) be performed first to the Viswa-linga. This is still being done today.