By accepting the popular worship, the Brahmans were able to oppose Buddhism with success.
We have no doubt that the Hindoo Triad came from the effort of the Brahmans to unite all India in one worship, and it may for a time have succeeded.

Images of the Trimurtti, or three-faced God, are frequent in India, and this is still the object of Brahmanical worship.

But beside this practical motive, the tendency of thought is always toward a triad of law, force, or elemental substance, as the best explanation of the universe.

Hence there have been Triads in so many religions: in Egypt, of _Osiris_ the Creator, _Typhon_ the Destroyer, and _Horus_ the Preserver; in Persia, of _Ormazd_ the Creator, _Ahriman_ the Destroyer, and _Mithra_ the Restorer; in Buddhism, of _Buddha_ the Divine Man, _Dharmma_ the Word, and _Sangha_ the Communion of Saints.

Simple monotheism does not long satisfy the speculative intellect, because, though it accounts for the harmonies of creation, it leaves its discords unexplained.