The Sri Rudram chant is an ancient Vedic hymn, and is the oldest example of a listing of various names of Lord Siva. Through the chanting of Sri Rudram, Lord Sivas various attributes and aspects are invoked and worshipped. Chanting the Rudram is considered to be of great benefit.According to mythology, Lord Shiva consumed the poison that came out of the ocean during its churning to save the world. It is believed that Lord Shiva held the venom in his throat, which turned blue as a result.Hence, Shiva devotees perform puja during this time as an offering to seek his blessings.On Pradosh or pradosham, Lord Shiva together with Goddess Parvati is believed to be extremely delighted, pleased and generous and hence devotess observe fast and worship to seek divine blessings. According to the Skanda Purana, one who observes this revered fast with devotion and faith is bound to possess contentment, wealth and good health and also attain spiritual upliftment and fulfilment of desires. It is believed that even a single glance of the deity on this propitious day will end all sins and bestow bountiful blessings and good fortune.Pradosh Vrat, which is also known as Pradosham in South India, is observed to seek blessings of Lord Shiva. Pradosh Vrat is observed on both Trayodashi Tithis, i.e. Shukla Paksha Trayodashi and Krishna Paksha Trayodashi, in lunar month. Some people distinguish between Shukla and Krishna Paksha Pradosham. When Pradosham day falls on Monday it is called Soma Pradosham, on Tuesday it is called Bhauma Pradosham and on Saturday it is called as Shani Pradosham.