Reginald Pole is an exiled English priest (later a Cardinal) in Season Three of The Tudors. He is played by Canadian actor Mark Hildreth. Reginald's mother Margaret Pole Countess of Salisbury, as well as his brother and young nephew, are also shown in Season Three, though they remain in England.
A devout Roman Catholic, Pole is a cousin of King Henry VIII via the House of York (he is a grand-nephew of Edward IV and Richard III) and one of the last official descendants of House Plantagenet. It is established that prior to his appearance in the series (probably during the beginnings of the English Reformation) Henry had patronized Reginald's clerical career and education abroad, but abruptly cut off his support when Pole refused an offer to become Bishop of York after the death of Cardinal Wolsey. Presumably, the offer was contingent on Pole swearing to recognize Henry as Head of the Church of England and joining the Protestant fold that Henry now supported. Whatever the case, Pole's relationship with the King fell apart after his refusal (despite attempts by his mother to mend the quarrel in 3.01), and he went into a self-imposed exile in Italy once the Reformation began in full force. Henry remained ill-disposed towards Pole, whose writings contained thinly-veiled criticism of Henry's reign, especially his remarriage to Anne Boleyn after nullifying his marriage to Catherine of Aragon; Reginald's mother, Lady Salisbury, was a devoted friend of Catherine. In order to keep up appearances, Henry is seen withholding his disdain for Pole at a court function where his mother was invited; telling Lady Salisbury that he is only mildly disappointed in the decline of his offer. Henry remarks in a good-natured way that he was interested in Reginald's academic progress and "I knew I had to thump him" by discontinuing paying Reginald's tuition, and accepts Lady Salisbury's excuse that her son is a humble scholar who does not seem to have the potential for a political career.
Pole is first seen attending a secret diplomatic meeting in Flanders, in 3.01 with the Ambassador of Spain, Signor Mendoza. Pole explains that Pope Paul III interprets the ongoing Northern Rebellion in England (known as the "Pilgrimage of Grace") as an opportunity for Catholicism to be restored to England without foreign intervention (as he has excommunicated Henry and declared him a heretic). As the rebels have great favor for Henry's Catholic daughter (and Pole's second cousin) Mary (who is also first cousin to the Spanish Emperor Charles V), Pole hopes the rebellion will force Henry to restore her to the succession. Mendoza asks him what the Pope has in mind if the rebellion fails, to which Pole declares that there is still one Catholic left with a strong claim to the throne of England- himself.
In subsequent episodes, Pole is taken under the wing of the German Cardinal Von Walthburg, who informs him the Pope has promoted him to Cardinal. Pole initially declares he is not worthy of the office, but Von Walthburg amusedly remarks that he should not presume to know better than the Pope's will. Von Walthburg informs him of events in England that work in favor of Catholicism, such as the rebellion known as the "Pilgrimage of Grace" in the North.
Although The Tudors often takes liberties with some of the historical events it covers, Reginald Pole's storyline is remarkably unchanged; he was charged by the Pope to organize support for the Pilgrimage of Grace and for taking the throne if it became possible to overthrow Henry. Henry VIII, enraged by Pole's criticisms and attempts to undermine his rule, indeed ordered several attempts on Pole's life; when these failed, he took revenge instead on Pole's family in England.
Reginald Pole is unseen after Season Three; he remained in Rome for the rest of Henry VIII's reign, as well as that of his Protestant son and successor, Edward VI. However, on Edward's death his Catholic sister, Mary I, took the English throne; Mary immediately welcomed her cousin Pole back to England, appointing him Archbishop of Canterbury after deposing the Lutheran Thomas Cranmer. Pole gave Mary wholehearted support in her campaign to stamp Protestantism out of England through the Marian Persecutions; however, despite his intentions, the burnings only inflamed the English people further against the Catholic Church. He died of illness the same day as his Queen.