Arjuna, the third among the Pandava brothers, the greatest archer of his times was cursed to become a eunuch by Urvashi, the celestial Apsara. This occurred when Arjuna spent five years of the thirteen year exile with Indra and learnt a lot about weaponry and warfare as well as the arts like dance and music. During a gathering, Arjuna kept on looking at Urvashi, totally awe -struck that she was the mother of his ancestors. Urvashi, misconstrued his locked glance to be a carnal invitation. Later, when she visited Arjuna in his room, he rejected her amorous advances. She threatened to curse him. He was willing to suffer the consequences but was not agreeable to any relationship with her other than of a mother and son.
Urvashi, cursed him to one year of impotence. As we all know, that whatever happens is for the good - howsoever bad it may appear at that instant. This curse was the only way to hide the mighty archer's bow-scarred broad shoulders during their 'agyaatvaas' in Viraatanagar. All the time he was cocooned with young girls and taught them music and dance.
The thirteenth year was approaching its end and Duryodhana was agitated that the Pandavas had not been located yet. Their detection would have entailed another thirteen years of exile and consequently a smooth-sailing tenure for the Kauravas. There was a strong suspicion that the Pandavas were hiding in Viraatanagar. It was decided that the Kauravas alongwith the Trigartas, would attack Viraatanagar. To oppose the attack, king Viraata took his army and the four Pandava brothers (still incognito), leaving the kingdom in the hands of the young Prince Uttara. King Viraata had underestimated the enemy. It was a two-pronged attack.
The young prince Uttara, whose charioteer had recently died in a battle, was at loss to tackle the situation. It was then that Arjuna, (as Brihannala, the eunuch) became prince Uttara's charioteer. Having once looked at the array of the enemy army, Uttara developed cold feet and tried to run back to the palace. Arjuna then disclosed his true identity to the young prince.
Their conversation is reproduced here. It is an extract from the Mahabharata, the original version in sanskrit, written by ShriVedavyaasa. Though, the sanskrit is fairly simple, the english translation is also provided nevertheless.
Viraataparva > Goharanaparva: Adhyaaya 44, Shlokas 7-22
दश पार्थस्य नामानि यानि पूर्वं श्रुतानि मे ।
प्रब्रुयास्तानि यदि मे श्रद्दध्यां सर्वमेव ते ।।
I have heard ten names of Partha in the past. If you can tell me those ten names, I shall have more faith in what you are saying.
हन्त तेऽहं समाचक्षे दश नामानि यानि मे ।
वैराटे श्रुणु तानि त्वं यानि पूर्वं श्रुतानि ते ।।
Son of Viraata, now, I will tell you my ten names that you have heard before.
अर्जुनः फाल्गुनो जिष्णुः किरीटी श्वेतवाहनः ।
बीभत्सुर्विजयः कृष्णः सव्यसाची धनंजयः ।।
Arjuna, Phalguna Jishnu, Kireeti,Shwetavaahana
Beebhatsu, Vijaya, Krishna, Savyasaachi, Dhananjaya.
केनासि विजयो नाम केनासि श्वेतवाहनः ।
किरीटी नाम केनासि सव्यसाची कथंभवान् ।।
How did you get these names Vijaya, Shwetavaahan, Kireeti and Savyasaachi?
धनंजयश्च केनासि ब्रूहि तन्मम तत्त्वतः ।।
तत् सर्वं यदि मे ब्रूयाः श्रद्दध्यां सर्वमेव ते ।।
सर्वञ्जनपदाञ्जित्वा वित्त्मादाय केवलम् ।
मध्ये धनस्य तिष्ठामि तेनाहुर्मां धनंजयम् ।।
I had conquered all the kingdoms and collected only their wealth as taxes; I stood among the vast wealth (Dhana). People therefore call me Dhananjaya.
नाजित्वा विनिवर्तामि तेन मां विजयं विदुः ।।
संग्रामे युध्यमानस्य तेनाहं श्वेतवाहनः ।।
जातो हिम्वतः पृष्ठे तेन् माम् फाल्गुनम् विदुः ।।
किरीटं मूर्ध्नि सूर्याभं तेनहुर्मां किरीटिनम् ।।
तेन देवमनुष्येषु बीभत्सुरिति विश्रुतः ।।
तेन देवमनुष्येषु सव्यसाचीति मां विदुः ।।
करोमि कर्म शुक्लं च तस्मान्मामर्जुनं विदुः ।।
In all the four directions on this earth, my glow is uncommon. My behaviour with everyone is the same --I'm impartial. All my actions are pure. Therefore, knowledgeable people call me Arjuna.
तेन देवमनुष्येषु जिष्णुर्नामास्मि विश्रुतः ।।
कृष्णावदातस्य ततः प्रियत्वाद् बालकस्य वै ।।
My complexion is dark. When I was young I had very attractive persona which made me very dear to my father. He used to call me Krishna.