The Pre-Sand War was just about the earliest history known about Minecraftia.
It was told in the Legend of Verigan special, a three episode mini-series of the Yogscast telling of an historic event. It tells the story of Professor Grizwold, who calls for his friend Verigan Antioch (Played by Simon), and his adventuring party: Karpath Antioch (Played by Lewis), Spacker LeChuck, Granny Bacon, the wizard Fumblemore, and Templar Adaephon. Grizwold called upon them because, in his studies of an ancient civilzation, he activated a strange portal, and suddenly monsters began to pour out of it, as well as causing various natural disasters. It was located inside of a a ruined castle. Eventually they managed to find the portal and attempted to disable it, however it did not work, and the portal stayed activated. Eventually, they decided to seal it up with dirt and cobblestone. Unfortunately, that also did not work and the evil continued to roam Minecraftia. This eventually lead to The Sand War, in which happened a few decades afterwards.