One day, King Shantanu of Hastinapur went hunting. Suddenly,
he smelt a sweet fragrance which was coming from a beautiful woman named
Shantanu fell in love with Satyawati and asked her fisherman father for
permission to marry her. The fisherman agreed on the condition that if
Satyawati had a son, he would become the next king. This made Shantanu
sad because he already had a son, Devavrata. Shantanu went back without
Satyawati. When Devavrata saw that his father was sad, he went to the
fisherman. Devavrata promised him that Satyawati's son would become the
next king instead of him. At this the clever fisherman said, "What
if your sons try to become king." To satisfy him Devavrata took a
vishma pratigya (strict pledge), never to get married and have children.
He then took Satyawati to the palace. Because of this strict promise, he
became famous as Bhishma.