In Act III, scene I of King John, Pandulph enters with a message from the Pope (Innocent III) for King John. The Pope had appointed Stephen Langton to be the archbishop of Canterbury. However, King John rejected this appointment, arguing that it was his right as king of England to appoint his desired archbishop.  Central to this conflict are the rival claims of Pope and King: “The Lord left to St Peter,” wrote Innocent, “the governance not of the church only but of the whole world.”   Though King John bristles at the idea of bowing to the authority of the Pope in Rome, Pandulph wastes no time in declaring John “cursed and excommunicate,” which officially excludes him from the sacrament and services of the Catholic Church (III.i.173) and authorizes his people to revolt against him (III.i.174-79). Historically, King John was indeed excommunicated by the Pope in 1209.  To the Elizabethan audience John would appear to be an early Protestant opponent of the authority of the Catholic Church.   The Act of Supremacy of 1534, established by Henry VIII, declared that the monarch not only ruled England but was head of the Church of England.   In 1570 the Pope declared Queen Elizabeth excommunicated from the Roman Catholic Church and thereby claimed to deprive her of the right to rule and the loyalty of her subjects.

“I raigne next under God, supreame head” 

The Troublesome Reign of King John, Pt. 1, 5.982 

But as we, under God, are supreme head,

So, under Him, that great supremacy

Where we do reign we will alone uphold

Without th’assistance of a mortal hand.

So tell the Pope, all reverence set apart

To him and his usurped authority.

King John, 3.1.155-60