Shantanu was the king of Kurukṣetra and was already ailing. His wife Satyavati, was the mother of Kṛṣṇa-Dvaipāyana and erstwhile wife of Maharṣi Parāśara. Parāśara was no more, having left the mortal coils and returned to the heavenly abode of the seers. In a previous era and during a previous incarnation, Parāśara had officiated as the Vedavyāsa and had foretold his able son Kṛṣṇa (Dvaipāyana) that he too would have to take on this task. To prepare the land to carry such a huge task it was necessary to perform the Vajapeya yajña and for this, the ailing and bedridden King Shantanu had to recover. Bhīśma used this as a test to check the prowess of Kṛṣṇa Dvaipāyana. The latter stood behind the kings bed and recited one of the powerful mantras of the Atharva veda and, to the utter shock and surprise of all, King Shantanu suddenly got up from the bed and agreed to go ahead with the Vajapeya yajña.
Kurukshetra is a place of historical and religious importance. Kurukshetra is in Haryana state of India. It is also known as Dharmakshetra as stated in the very first verse of the Bhagavat Gita – धर्मक्षेत्रे कुरुक्षेत्रे समवेता युयुत्सवः | मामकाः पाण्डवाश्चैव किम् अकुर्वत संजय ||
Rishi Kṛṣṇa Dvaipāyana used this golden opportunity of the Vajapeya yajña to launch the mission of recompilation of the Veda. He had previously discussed this matter with his father Maharṣi Parāśara. While his great-grandfather had been of the opinion that the Veda should be in three parts – Rk, Yajur and Sama, both Parāśara and Kṛṣṇa Dvaipāyana had opined that the fourth part – Atharva Veda should also be added as an integral part of the veda. This had become easier as the great Atharvan Rishi was now his father-in-law.
Bhīśma spearheaded and got the project commissioned by the noble Kuru dynasty and the recompilation of the Vedas took twelve years to complete. King Shantanu was already bedridden and passed but the project did not stop and the kṣatra tejas of Bhīśma, who had become the regent for the young King Vichitraveerya, the son of King Shantanu and Queen Satyavati, provided the necessary support in every form and manner.