The inception of yoghurt can be traced to the Middle East of the Neolithic age. The first historical reference to any fermented milk product, is found in the Bible, Genesis 18.8, from which we can deduce that 13 centuries before the birth of Christ, the Nomadic shepherds of Mesopotamia were already eating yogurt.
There is an alternative version, a Mongolian legend:
The hero is a certain Mongolian horseman from Ghengis Khan's cavalry. On one of his trips to the desert, chance brought him to a village recently conquered by Ghengis Khan. Exhausted and parched from the journey he asked for water to fill his flask. The subjugated villagers were not in the least bit pleased by his arrival and wanting to take revenge on the weary horseman for all the slights suffered at the hands of their conquerors, they implemented a satanic plan: they filled his flask with milk, instead of cool water. The unfortunate horseman thanked them and set off on his journey through the desert. It didn’t take him long to realise that in his flask there wasn’t a drop of water; instead a white, unguent cream had formed. The climatic conditions had created a fertile environment for the makings of yoghurt. With no alternative in sight, the horseman took a sip of the white cream, which he found particularly pleasing in flavour. As a result, the Mongolians fed themselves with yoghurt when there was no other available food and used it as a way to preserve their meat. Not only was our hero saved from thirst, he also offered his nation a notable service: the discovery of a new and nourishing food.