Sure markets may be older than libertarians, but even though libertarians didn't exist to enunciate libertarian theory back then, the fundamental libertarian phenomenon of non-aggression and voluntary exchange as you mention was indeed present.

But most non-libertarians believe in non-aggression and voluntary exchange too. They just argue that some taxes aren't aggression and some exchanges aren't really voluntary.

These where often rather agressive trades, even without violence actually occurring it's threat was still on the table.