Who started capitalism?
It depends on how you define capitalism. As an explicit theory, capitalism was created by ADAM SMITH in the late 1700s. However, the idea that groups of people could gather money together and freely spend it in the marketplace, as opposed to a barter system or government-controlled marketplace of some variety (like feudalism or mercantilism) is much older than Adam Smith and could be said to have started in the 1200s and 1300s when systems of credit and preliminary banking were first introduced by the Crusading Knights.
No one knows; it was just another way for thousands of poor people to survive. Some historians believe that capitalism or the "spirit of capitalism" started in the 14th century. See http://en.wikipedia.org/wiki/Capitalism#History. I know its from Wikipedia but it does have links to other more creditable web sites about capitalism.