Sri M said ...

If you go back to ancient times and look, the concept of Shiva is always constant. It doesn’t come; it doesn’t go. If it has to manifest, it manifests as Shiva. There is no need to change anything, therefore, Shivam. Shivam is a concept of the supreme, original, pure, all-pervading Being, which the Isha Vāsya Upanishad describes as “Ishavasyam Idam Sarvam.” That Supreme Being pervades everything here.