Most people think liberalism comes from Marxism-Leninism. It actually pre-dates the Communist Manifesto. Robert Owen was a British industrialist turned socialist. He founded New Lenark in Scotland to try to employ his social theories, but his partners bailed on him.

Owen was the prototype of modern liberals. He rose from poverty, became very wealthy, then tried to reorder the world around him without applying his theories to himself. When he came to America, he was feted by Congressional Dems. He went around giving speeches while his son tried to make everything work in New Harmony. The project attracted people who were unemployed and who had lost much in the financial panics of the early-mid nineteenth century. After just under three years, the project failed, having not attracted farmers, craftsmen, and skilled workers.

Owen went on holding anti-religion debates with the likes of Alexander Campbell and then went back to England where his writing took on a quasi-religous tone.

If you like reading history, check out his banner work, "The Book of the New Moral World. It's very eye opening and you will see where modern liberals' roots really come from. You have to know the enemy.

https://archive.org/details/bookofnewmoralwo00owen