Depends how people subjectively interpret "as we know it today"
Personal property and voluntary trade (capitalism) date back very far, and the only thing preventing flourishing is the government constantly getting in the way of capitalism imho!
Discussion
Owning things and trading them is necessary but not sufficient to describe capitalism. Capitalism can only exist as an economic system because of liberal government and its understanding of human nature. As I understand it, the foundation of liberalism gives way to the nation state and capitalism (or worse, socialism) as a package deal because of its radical individualism.