Many ancient Shiva Temples could be witnessed in Kashi. one of them is the Amareshwar Temple. The importance of this Temple is mentioned in Kashi Khand.
Legend
According to Kashi Khand, Chapter 69, the spot where Lord Shiva donned Gajasur’s skin after slaying him was named Rudra Vasam. (Please refer to Krithi Vaseshwar.) When Nandi presented his prayers and mentioned that there are 68 sites of devotion devoted to Lord Shiva in this sacred spot, the Lord, in his incarnation as Krithi Vaseshwar, was sitting with Goddess Uma Devi. Nandi brought several idols/Shiv Lings from other places and put them in Kashi.
Amareshwar, a Ling from Ganga Sagar Teerth, has emerged in the Holy City of Kashi. Devotees who worship this ling will have a long and happy life, free of the dread of death.