Libertarianism is explicitly based on the ideas of Manchester School Liberalism. The British Liberal Party of the 19th Century was all about free market ideology, in contrast to the (theoretically) more centrist modern party. In Victorian Britain, Liberal own you.
The original Liberals were actually a bunch of mill owners in 19th Century Manchester (at the time the most technologically advanced city in the world) who got together to ask challenging questions like “why should we have to pay taxes?” and “what if we basically owned our employees? And their children”.
Marx and Engels lived there for a time and witnessed the conditions the working people lived in first-hand.