When was  minecraft
  first created?

Minecraft was created by a man named notch Or
  Markuss Person in may 10 2009 ,
  Minecraft
  is A Sandbox game created by notch It was meant to be small But it turned out
  to be a big hit, Minecraft was first created in May, 10, 2009
Markus Person Posted a alpha version of Minecraft on may 17
2009

Who made minecraft?

The people who made Minecraft are Carl Manneh, Daniel
Frisk,  Daniel Kaplan, 
Jakob Porser, Jens
Bergensten, Junkboy, Narkus Persson, Tobias Mollstam , Those were all the people
who made MINECRAFT, Markus Persson Made minecraft (notch) In
  may 10 2009, Markus Persson

What was minecraft's first purpose?

It was supposed to be a little indie game but then it got
HUGE!,  There was supposed to not be a purpose of minecraft it was
supposed to make people dig holes but then it got big,  You just needed wood a hole and a crafting table

References

http://wiki.answers.com/Q/When_was_minecraft_first_made
http://en.wikipedia.org/wiki/Minecraft
http://www.pcgamer.com/2012/02/06/the-first-moments-of-minecraft/
http://answers.yahoo.com/question/index?qid=20130329061104AANGqiP
www.minecraftwiki.net/wiki/Markus_Persson
https://minecraft.net/game
www.minecraftwiki.net/wiki/Tutorials/Beginner's_guide
www.escapistmagazine.com/.../8916-What-Purpose-Minecraft-Zombie
www.wired.co.uk/news/archive/2011-11/.../minecraft-career