Tamil Sangam Literature (early centuries CE) mentions Murugu as a nature spirit worshipped with animal sacrifices and associated with a non-Brahmanical priest known as a Velan , a name later used to refer to the deity himself. The worship of Murugu often occurred in the woods or in an open field, with no particular associated structure. The rituals practiced included the Veriyaattu, a form of ritual-trance-dancing, which is still a common part of Murugan worship in Tamil Nadu, Kerala and Malaysia. Murugu was believed to hold power over the chaotic and could be appeased by sacrifices and Veriyaattu to bring order and prosperity.
Tolkappiyam, possibly the most ancient of the extant Sangam works, glorified Murugan, " the red god seated on the blue peacock, who is ever young and resplendent," as " the favoured god of the Tamils.". The Sangam poetry divided space and Tamil land into five allegorical areas (tinai) and according to the Tirumurugarruppatai ( circa 400-450 CE) attributed to the great Sangam poet Nakkiirar, Murugan was the presiding diety the Kurinci region (hilly area). (Tirumurugaruppatai is a deeply devotional poem included in the ten idylls (Pattupattu) of the age of the third Sangam).
The other Sangam era works in Tamil that refer to Murugan in detail include the Paripaatal, the Akananuru and the Purananuru.
One poem in the Paripaatal describes the veneration of Murugan thus:
"We implore thee not for boons of enjoyment or wealth, But for thy grace beatific, love and virtuous deeds".
Architectural findings of pottery in several places in Tamil Nadu and elsewhere had ideographic inscriptions of this name as far back as 3rd century BCE. According to noted epigraphist Iravatham Mahadevan, the ideographs signify a brave warrior capable of killing evil demons to save the devoted.
Lord Muruga was worshipped for giving the meaning of the Pranava Mantra (OM) to Lord Shiva himself.