WHAT IN A MIDDLE NAME?

I  have always wondered why people are given middle names.Is it to past a family name or part of a long forgotten tradition,for years i hated my middle name would not even use it.Why?well due to when at primary school i was asked to play a well known roman-MARK ANTONY,I ran away due to fact had to kiss a girl,yuck,yes it is sad,thats why i did not use for ages.