Directors realise that audiences are not likely to have much grip on Shakespeare’s King John

Directors realise that audiences are not likely to have much grip on Shakespeare’s King John. They hardly know what to expect, except perhaps something about Magna Carta, which doesn’t figure in the play at all. Perhaps Shakespeare had never heard of it. In any case, he presents King John as a patriot, misguided, certainly, when he connives at the torture of his nephew little Prince Arthur, but standing out to his last breath against France. In the high Victorian theatre the actor playing the king used to sweep the crown from his head during his death scene and even hurl it into the wings, partly to indicate magnificent failure, and partly to keep some attention for himself. By that time the audience had already seen little Arthur die and his mother Constance run mad, their handkerchiefs were soaked, they had no more tears to shed. King John himself was left ranting on, against unfair competition.

P. Fitzgerald, At Freddie’s (1982), 89

Foul as it is, Hell is made fouler by the presence of John

A man of forty-eight years, who had presided over the disintegration of the great Angevin Empire and brought the kingdom of England to its knees. A number of chroniclers confidently predicted that the late king would be condemned to Hell. One even added that: 'Foul as it is, Hell is made fouler by the presence of John,'

T. Asbridge, The greatest knight: the remarkable life of William Marshal, the power behind five English thrones (2015), 338

He is citing Matthew Paris, I think. This otherwise excellent book is marred by the absence of proper footnotes and instead their irritating replacement by textual references in the back