David posted on telegram chat and copied to share here

Just a quick one for anyone who is learning to use thees and thous… some get caught using “thy” to mean “I” or “my”, e.g. “Thyself is in” or “Thy have (or has) done this or that”.
Thy means your, it does not mean I nor me nor my.
I and me and my remain unchanged if moving to those older pronouns.
Ye => You (as plural)
Thee => You (as object)
Thou => You (as subject)
Thy => Your
Thyself => Yourself
Thine => Yours
I => I
My => My
Me => Me
Mine => Mine
Could be fairly hilarious telling a male magistrate “Thou are a living woman” or vice versa…