1 Robert Pakington, MP: I have Mr Arden’s Last Will and Testament here. Allow me to read it out.
2 Robert Pakington, MP: “I, Robert Arden, being of sound mind,” etc., etc... “hereby bequeath all my worldly possessions to my dear wife, Mrs Arden.”
3 Robert Pakington, MP: He called you Mrs Arden?
4 Mrs Arden: You say that like my name is some sort of mystery!

In our real history, it's known that William Shakespeare's mother was one Mary Arden, daughter of Robert Arden (who has been killed in our story), and... his wife. There are no extant records of the name of Robert's wife, Shakespeare's maternal grandmother.

I considered giving her a name, but decided it would be for the best if I didn't muddy the waters of historical fact by claiming to know her name. If I did give her a name, it'd probably be enshrined in Wikipedia, and 100 years from now everybody would know for a fact that Shakespeare's maternal grandmother's name was Daenerys Bellatrix Arden.