What's the Origin of Scot Free?

I’m reading a book that used the term “Scot free” referring to someone getting away with murder. I’ve used the phrase for years but I guess I’ve never seen it written. I was surprised to see the S in Scot capitalized so I am assuming it relates to a Scottish origin. Any ideas?

According to this article:

Scott Free is the son of Highfather of New Genesis. He was one of the children exchanged between New Genesis and Apokolips as part of a peace treaty/human sheild agreement between Highfather and Darkseid. Darkseid’s son involved n the exchange grew up to be known as Orion, while Scott Free escaped from Granny Goodness’ orphanage and took the name of Mr. Miracle, the World’s Greatest Escape Artist.

And Scott’s wife is hot.