Brahmaa was born from Naaraayan's navel, Vishnu is the son of Kashyap and Aditi but what about Shiv? Who are his parents?

It is said that once Brahmaa and Vishnu were quarreling on the matter "who was greater between them". As the arguments got hotter, a shining column rose between them and reached high up to sky. Both Brahmaa and Vishnu got surprised to see the column and looked at each other in wonder as "where it came from?" They both together decided to search for its beginning and end. Brahmaa Jee suggested that he was going up to find its top and asked Vishnu to go down to see its origin. Brahmaa Jee took a swan's form and flew upward, Vishnu took the form of a white boar and ran downwards.

After a while Vishnu appeared and told that he could not find its origin, in the meantime Brahmaa Jee also appeared there and told that he could find the top and presented witnesses, one of them was the Kaamdhenu cow. Seeing this drama, Shiv appeared there and said - "Brahmaa, you are telling lie by saying that you have found the top, while you did not find any. I curse you that you will not be worshipped by anybody on Prithvi, and since you told lie, I cut your that head by which you told the lie." Saying this Shiv cut Brahmaa's that head by which he told the lie. Brahmaa had five heads before, after this incident, he had only four heads.