Minecraft is the sandbox game, developed by Markus Notch Persson and currently managed by Jens Bergensten, that Hexxit is based off of. It provides much of the programming and block content that Hexxit involves. and the mods that make up Hexxit would not work without it.
History
Conceived sometime in 2009 and born May 16, 2009, "Minecraft: Order of the Stone" was, according to PC Gamer, first officially noticed about 8 minutes after release.
Since Minecraft was released, it has seen 7 phases, 36 mobs (as of update 1.8), and millions of account purchases.