Mandapalli is Situated 38 Km from Rajahmundry, 60 Km from Kakinada and 30 Km from Amalapuram.In the days of yore, this locality was the holy ashram of the sage Dhadhichi Maharshi. This hermit Dhadhichi has done a supreme sacrifice of donating his valuable spinal cord for the mighty and powerful weapon popularly known as Vajrayudha of Lord Indra, which was employed to kill the deadly asuraas. The weapons wielded by the eight suras in the eight directions called astadikpalakas, killed innumerable ghostly demons. To avenge the death of these demons certain other demons called Aswadha and Pippale invaded the area under reference and brought about untold havoc.
At last the eminent hermit 'Agasta' living in South India obliging the prayers of the people and their King assured them of the death of these giants in the hands of 'Lord Sani' the son of the Sun God. Further they appealed Sani Deva to protect them by putting an end to these terrible monsters 'Aswadha and Pippala'. Sani made up his mind to kill the monsters for which he had to wage a war for one long year and killed them. As a mark of this glorious victory he installed an idol of 'Lord Siva' here. This instillation of Sivalinga; became necessary for atoning sins of kings that belonged to Kasyapa Dynasty.
So in obedience to the sacred advise of the Maharushis, Sani atoned the sin of Brahma hatya by installing and adoring Lord Siva.
After that Sani declared that whoever worship this Linga by offering the dear gingelli oil etc. would be blessed. He further said that he would bless such devotees obviating all evils that befall them due to the curse Satru.For this reason, Lord Eswara is popularly known as Saneswara or Mandeswara. So people offer gingelli products which are dear to Sani who is the diety here.
She is sponsored by Siva. This Linga is said to be one of the Sapta Maharshis. There is also another version that the wives of the Saptha Maharshis installed this lingam here.