In OTL at least one of the 'regicides' was proud to state that they acted openly and not 'in a corner' (as had other kiliings of English KIngs had been)
Now had Charles I been poisoned, or died 'escaping' what would have occured
Could Charles II have done a deal?
Now had Charles I been poisoned, or died 'escaping' what would have occured
Could Charles II have done a deal?