Śvetāśvatara Upaniṣad
Sanskrit · Upaniṣad · c. 4th–2nd c. BCE (uncertain)
Upaniṣadic / proto-Śaiva
An early text presenting Rudra-Śiva in theistic terms; often cited as a bridge to later Śaiva theology.
Dating is contested; its theism has been read both as early Śaiva and as broadly Vedāntic.