Draupadi needs no introduction. She was the mysterious, fiery yet compassionate queen of the five Pandava brothers. Draupadi was the wife of 5 Pandavas.
Draupadi was born young. According to the Mahabharata, Draupadi was born from "Yagya kunda" of Maharaj Drupada. As she is daughter of Drupada that's why she is known as Draupadi.
When Pandavs were staying as a guest of Drupad in Panchal and until Yudhisthira was crowned king of Indraprasth and he started living there, there was no rule with regards to sharing of draupadi.
Then Pandav makes a rule that "When Draupadi will be with one of the brothers, the other four will not see them / will keep away. And if they break this rule then the brother will have to go for exile for 12 years".
As always, this story was to establish the second part of the epic and it was the exile of Arjuna. One day a Brahmin reached Arjuna's door to seek help, the bandits ran away with his cows. Following his code of religion, Arjuna decided to help the Brahmin but his weapons were in the room of Draupadi and She was with Yudhishtir at the time. Even after knowing the rule, Arjuna went ahead, retrieved his weapons and proceeded to kill the bandits. On returning, he went into exile for 12 years.