Arjuna pronounced [ɐrˈɟunɐ] in classical Sanskrit (lit. bright or silver (cf. Latin argentum)) is the third of the Pandavas and, with Krishna, is considered the hero of Hindu epic Mahabharata. He plays the listener in the Hindu scripture, the Bhagavad Gita which is a philosophical conversation between Arjuna and Krishna. Arjuna, considered the finest archer and a peerless warrior by many notable figures in the Mahabharata such as Bhishma, Drona, Krishna, Vidura, Sage Naradha and Dhiritharashtra, played a key role in ensuring the defeat of the Kauravas in the Kurukshetra War. He is the only undefeated hero in the Mahabharata. Arjuna was an avatar of Nara, who along with the avatar of Narayana, Krishna, established Dharma in the Dvapara Yuga.^[1]
Once, a Brahmin rishi named Kindama and his wife were making love in the forest when Arjuna's father Pandu accidentally shot at them, mistaking them for deer. Before dying, Kindama cursed the king to die when he engages in intercourse. Due to this curse, Pandu was unable to father children. As an additional penance for the murder, Pandu abdicated the throne of Hastinapura and his blind brother Dhritarashtra took over the reins of the kingdom.^[5]
After Pandu's disability, the Pandavas were conceived in an unusual way. His mother, Queen Kunti, had in her youth been granted the power to invoke the Devas by Rishi Durvasa. Each Deva, when invoked, would bless her with a child. Urged by Pandu to use her boons, Kunti gave birth to Arjuna by invoking the Lord of Heaven, Indra. King Pandu and Kunti purified themselves by severe austerities to Indra for one year before he was born. No other birth in the Mahabharata except Krishna's was celebrated by the devas, sages and apsaras.
Along with other Pandava brothers, Arjuna was trained in religion, science, administration and military arts by the Kuru preceptors, Kripa and Drona. Specifically, he became a master in using the bow and the arrow. Arjuna’s strength lay in his extraordinary levels of concentration. In a famous incident under Drona’s tutelage, Drona deemed none of his students other than Arjuna had the steadfast focus to shoot a bird on a tree and was proved right by Arjuna.^[6]

Arjuna’s Tirtha-yatra

the Swayamvara of Panchala's princess, Draupadi

The Pandavas attended the Swayamvara of Panchala's princess, Draupadi, disguised as Brahamans. Among all great kings and other Kaurava princes, Arjuna was the only one to shoot the arrows to break a fish doll, as demanded by the Panchala King Draupada. As per Kunti's wish, along with his brothers, Arjuna was married to Draupadi, who gave birth to a son, Srutakriti.^[7]
The brothers followed Narada’s advice on a sharing arrangement with regard to Draupadi: each brother will have exclusive rights over her for a year, after which the mantle will shift to the next brother. Moreover any brother intruding on the privacy of the couple will have to go on a 1 year Tirtha-yatra (pilgrimage). However during a freak incident involving chasing out some bandits, Arjuna was forced to enter into the private space of Yudhistira and Draupadi. He accepted the punishment agreed with Narada and set off on a 1 year pilgrimage.