I have a couple questions that all deal with the act of dueling for ones honor or for settling disputes throughout history.

When did dueling begin and was it limited to a certain class/gender or could anybody challenge anybody to defend their honor or settle a dispute?

What were the general rules of a duel? Was there any sort of written code duelists must follow or were the rules decided by some sort of mediator? Were there any rules that were not "written" but were common to follow to show respect for your opponent?

How were weapons chosen and did bare knuckle boxing ever occur in duels or was it considered too uncivilized to box in a duel?

How often did duels result in death (on the spot or from injuries)?

When was dueling phased out or is it still legal today in some parts of the world and who were the most successful/famous duelists throughout history?

Thanks :)