The Mahabharata/Book 1: Adi Parva…
“ Vaisampayana said, 'Desirous of giving his grandsons a superior education, Bhishma was on the look-out for a teacher endued with energy and well-skilled in the science of arms. Deciding, O chief of the Bharatas, that none who was not possessed of great intelligence, none who was not illustrious or a perfect master of the science of arms, none who was not of godlike might, should be the instructor of the Kuru (princes) , the son of Ganga, O tiger among men, placed the Pandavas and the Kauravas under the tuition of Bharadwaja's son, the intelligent Drona skilled in all the Vedas. ”
