The origin of cheese making range goes from around 8000 BCE (when sheep were first domesticated) to around 3000 BCE. It is probable that the process of cheese making was discovered accidentally by storing milk in the stomach of an animal, making the milk turn to curd and whey by the rennet from the stomach.
Cheese making may have also begun by the pressing and salting of curdled milk to preserve it. Then they might have observed that the effect of making milk in an animal stomach gave more solid and better-textured curds, and therefore added of rennet.
There has been found evidence of cheese making in Egyptian tomb murals from 2000 BCE. The earliest cheeses were quite sour and salty, similar to the texture of feta cheese.
Cheese produced in Europe needed less salt for preservation because of the different weather form the middle East. With less salt and acidity, the cheese would have more microbes and molds, giving aged cheeses their pronounced and interesting flavors.
information from: www.wikipedia.org and www.french-cheese.com
