I'm going to harp on this
Why are you say like 15 Eighty for? it's 1580
It's called "artistic license" and used in the same manner that modern artists paint a vision, not a photograph.
Wikipedia:
Artistic license (also known as art licenselo, historical license, dramatic license, poetic license, narrative license, licentia poetica, or simply license) is a colloquial term, sometimes a euphemism, used to denote the distortion of fact, alteration of the conventions of grammar or language, or rewording of pre-existing text made by an artist in the name of art.