The Vedic knowledge existed before the creation of this universe and is given by Lord Krishna to the first living being at the beginning of creation, which was 155.522 trillion years ago. The Vedic knowledge was last written down 5000 years ago by Lord Krishna in His form as Veda Vyasa, the compiler of the Vedic scriptures.
“I am seated in the hearts of all living beings, from me comes memory, knowledge, and forgetfulness. I am the compiler, knower of the Vedas, and known by all the Vedas.”(Lord Krishna, Bhagavad-Gita 15.15)
All the true knowledge that can be found in the non-Vedic scriptures originates from the Vedic scriptures. This can be proven by the fact that the Vedic scriptures came first and all the true knowledge found in the non-Vedic scriptures can be found in greater details in the Vedic scriptures, and the Vedic knowledge is vast compared to the non-Vedic knowledge.