Mbh 1.133.6

“Thus addressed, Drona replied unto the princes, saying, ‘Do ye repair unto Bhishma and describe to him my likeness and skill. The mighty one will recognize me.’ The princes then saying, ‘So be it,’ repaired unto Bhishma and telling him of the purport of that Brahmana’s speech, related everything about his (extraordinary) feat. Hearing everything from the princes, Bhishma at once understood that the Brahmana was none else than Drona, and thinking that he would make the best preceptor for the princes, went in person unto him and welcoming him respectfully, brought him over to the place. Then Bhishma, that foremost of all wielders of arms, adroitly asked him the cause of his arrival at Hastinapura. Asked by him, Drona represented everything as it had happened, saying, ‘O sir, in times past I went to the great Rishi Agnivesa for obtaining from him his weapons, desirous also of learning the science of arms. Devoted to the service of my preceptor, I lived with him for many years in the humble guise of a Brahmacharin, with matted locks on my head. At that time, actuated by the same motives, the prince of Panchala, the mighty Yajnasena, also lived in the same asylum. He became my friend, always seeking my welfare. I liked him much. Indeed, we lived together for many, many years. O thou of Kuru’s race, from our earliest years we had studied together and, indeed, he was my friend from boyhood, always speaking and doing what was agreeable to me. For gratifying me, O Bhishma, he used to tell me, ‘O Drona, I am the favourite child of my illustrious father. When the king installeth me as monarch of the Panchalas, the kingdom shall be thine. O friend, this, indeed, is my solemn promise. My dominion, wealth and happiness, shall all be dependent on thee.’ At last the time came for his departure. Having finished his studies, he bent his steps towards his country. I offered him my regards at the time, and, indeed, I remembered his words ever afterwards.