In earlier part of her life, Sita while playing with her sisters had unknowingly moved the table over which the "Shiva Dhanush" had been placed; which was something no one in the palace could do. This incident was however observed by King Janaka and he decided to make this incident as the backdrop for swayamvar.
Later, Janaka had announced that whoever wanted to marry Sita had to do so only after lifting (which was itself a difficult job) the bow from its place and stringing it. The bow was broken by Lord Rama when he attempted to string the bow, during the swayamvar of King Janaka's daughter, Sita, whereby he won the hand of Sita in marriage.
After the swayamvar, while Rama, Sita and Lakshmana were on their way to Ayodhya, Parashurama confronted and challenged Rama for breaking the bow. Dasharatha told Parashurama the incident which had happened in the palace. But Parashurama wouldn't control and brought Lord Vishnu's bow. He then asked Rama to string the bow and fight a duel with him.
Rama respectfully bows to Parashurama, and within a twinkling of an eyelid snatches the bow of Vishnu, strings it, Rama then shoots the arrow up into the sky with Vishnu's bow, performing a feat true to his supreme, divine nature with his natural weapon.
Then Parashurama left this world to mahendra Parvat.
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