Hinduism or the Hindu philosophy which the world know now is a rich practical and Social relegion in the world.  Who started or when started is not known.
That much old is the history for this philosophy.  The Name "Hindu" was given to this relgion later to identify. 

We human being have limitation in understaning things which has no forms.  So when a religion has no name we could not indentify.  Hence the name "Hindu" was given to this pretty old religion.