Lord Shiva himself has declared this spot as his Royal residence. The mother of Goddess Parvati felt ashamed that her son-in-law had no decent dwelling. To please Parvati Devi, Shiva asked Nikumbha to provide him with a dwelling place at Kashi. On the request of Nikumbha, Aunikumbha a Brahmin made Divodas construct a temple for the Lord here. The pleased Lord granted boons to all his devotees. But Divodas was not blessed with a son. Angry Divodas demolished the structure. Nikumbha cursed that the area would be devoid of people. Listening to the pledges of the repenting divodas, Lord Siva once again took residence here permanently. The Lord along with Parvati Devi once again started blessing his devotees with wonderful boons.
Parvati Devi was so pleased that she offered food (annam) to one and all and hence is worshipped as Annapoorani. The Lord himself is seen with a bowl in his hands asking for annam from the seated Devi at the Devis shrine adjacent to Viswanathas shrine. This is considered to be one of the 52 Sakthipeedams (the place where Parvathis left hand fell, when her corpse was cut by Mahavishnus sudarshana chakram).
source : jyotirlingatemples