Bhishma was born as the eighth son of the illustrious King Shantanu and Ganga. As per the Mahabharata, Shantanu saw Ganga on the banks of river Ganga (Ganges) and enamoured of her beauty, asked her to marry him. She agreed but with the condition that Shantanu would never question her, no matter what her actions — if he ever broke his promise, she would leave him, never to be a part of his life again. Shantanu readily agreed to this seemingly harmless condition and was thus married to Ganga. Eight children were born in this marriage, the eighth of which was Bhishma himself. The seven siblings born before him were drowned by their mother Ganga in order to break their curse — as they were incarnations of the aforementioned, who do not like to live the life of Humans. Shantanu silently bore the torture of watching his wife drown his offspring seven times. However, when Ganga was about to drown Bhishma, Shantanu could no longer contain his anguish and burst into protest. Ganga, aware of the eighth child’s destiny to live a long life on earth, did not drown the child. However, since Shantanu had broken his promise given to her at marriage, she left Shantanu promising to return the child to him once he is grown up.During his childhood, was taught political science and other subjects by and ,gurus of the Devas and Asuras respectively; Vedas and religious scriptures by the sage Vasishtha; Sage Markandeya was his spiritual guru. On Ganga’s persuasion, Devavrata was taught martial arts, military sciences and the use of weapons by Parashurama. His banner in battle was a golden palm tree.
Bhishma means He of the terrible oath, referring to his vow of lifelong celibacy. Originally named Devavratha, he became known as Bhishma after he took the bhishana pratigya (‘terrible oath’) — the vow of lifelong celibacy and of service to whoever sat on the throne of his father (the throne of Hastinapur). He took this oath so that his father, Shantanu could marry a fisherwoman Satyavati — Satyvati’s father had refused to give his daughter’s hand to Shantanu on the grounds that his daughter’s children would never be rulers as Shantanu already had a son (Devratha).
Bhishma is the one who witnessed the Mahābhārata completely from the beginning since the rule of Shantanu. In the great battle at Kurukshetra, Bhishma was the supreme commander of the Kaurava forces for ten days compared to Drona’s five, Karna’s two and Salya’s one-the last day. He fought reluctantly on the side of the Kauravas; nevertheless, he gave it his best effort. Each day he was killing around 10,000 soldiers of Pandavas.
During the war, an invincible Bhishma wreaked havoc on the Pandava army for ten days but he had vowed not to kill Pandavas, his grandchildren. When provoked by Duryodhana, he relented and said that either he will kill Arjuna the next day or make Krishna pick up a weapon and force him to break his vow. In the battle that ensued the next day, Bhishma was very near killing Arjuna when Krishna broke his vow and picked up a wheel against Bhishma.
This incident is significant in that it shows that Krishna was prepared on one hand to break his own vow to defend his beloved Arjuna, on the other he helped his devotee Bhishma to keep his vow of either killing Arjuna or forcing Krishna to pick up a weapon. And here lies the difference in the characters of the two men – one ready to sacrifice all to keep his vows, the other ready to do all it takes to establish dharma.
Krishna then asked Arjuna to go to Bhishma and understand how he could be killed and Bhishma obliged by telling them he would not raise his weapons against a woman or a transgender. Arjuna then fatally injured Bhishma when he laid down his weapons seeing Shikhandi, or Amba reborn.
Bhishma had the boon of deciding the manner and time of his death and even though he was in great pain, he did not yet wish to leave this world. And this is when Krishna gave a boon to Bhishma that he would not feel any pain from his wounds and encouraged him to share his immense knowledge of statesmanship with Yudhishthira, the future king of Hastinapur, thereby ensuring that his name would forever be etched in history not only for his vows and valiance, but also as a great scholar and statesman.