I understand what you meen but I'm not drawing historical picture, I'm drawing illustrations based on a romantic story. Cyrano de Bergerac has already been illustrated in various period and it didn't really mater for me to respect historical elements this time. Go to see this link for example : [link]
But I certainly agree with you if my goal was drawing historical picture well...It would be really important to make more research.
When you make something in historical reality, you need reality in details. People looking at it. Cyrano is of course romantic story, but romantic story in XVII-th century french costume. Mixing details is allowed, when mixed parts have special meaning... But to be more constructive: this can help: [link] [link] [link] [link]
I like your drawings, really. They have special taste...