I once worked in England with a guy called Thane. A cool Anglo-Saxon title meaning warrior lord. Any fame it might have probably comes from Macbeth. Now it is very rare, only 3/yr in UK and 43/yr in US.
While I need to brush up on my Shakespeare, I do recognize that name from Skyrim
Isn't Thane more of a landholder, who could or could not also be a warrior but either way it isn't implied in the title? I think it is equivalent to a Baron.