How do I make sense of the 終助詞 もん as in
Although I have only heard it in 時代劇 speak, I guess it comes from もの, which I think should be も + の.
But what も can follow the 終止形 and what の can follow that も. Is も the same も that roughly means "also"? Is の the nominalizer の here?
P.S. I am not asking what it means, when it is used, etc. I want to know how to make sense of it grammatically. At the moment, it has also been suggested that もん・もの derived from 物, but it seems to follow different rules than what one would expect of a particle derived from a noun.