From Strange Rebels: 1979 and the Birth of the 21st Century, by Christian Caryl (Basic Books, 2014), Kindle Loc. 1902-1919:
John Paul II had begun to think about making a pilgrimage to Poland within days of becoming pope. The coming year of 1979 offered a perfect occasion for a visit. It was the nine hundredth anniversary of the martyrdom of Poland’s greatest saint, Stanisław Szczepanowski. He was the Polish equivalent of Thomas à Becket, a man who stood up to the highest power in the land in the name of his faith. In 1072 Szczepanowski became the bishop of the city of Kraków. What we know of him is blurred by legend, but it is clear that he must have been a man of strong will and stubborn principles. He soon became embroiled in a feud with the king of Poland, a brutal character by the name of Bolesław the Bold. (As is so often the case in history, the nickname “bold” was really a euphemism for “psychopathic.”) Bolesław refused to put up with the churchman’s challenge to his authority, and he demanded the death of Stanisław. But no one would carry out the order, so Bolesław did the deed himself. He is said to have cut the bishop down while he was conducting a mass. Few of the king’s deeply Catholic subjects were willing to countenance the killing, and Bolesław soon lost his hold on power. Stanisław, on the other hand, quickly achieved sainthood as one of Poland’s greatest martyrs.
Though many of the details of Stanisław’s death remain mysterious, one thing we do know for certain is that it happened in 1079. A thousand years might seem like a long time to most of us, but the particulars of the story—the principled stand of a bishop of Kraków laying bare the moral bankruptcy of untrammeled state power—gave it unnerving relevance to Poland’s situation in 1979. The Communists certainly thought so, in any case.
So the announcement that John Paul II intended to return to Poland to celebrate the nine hundredth anniversary of Stanisław’s martyrdom sent a shiver of dread through the ranks of the United Polish Workers’ Party. “The cause of the bishop’s death was a conflict with the king,” one internal party memorandum noted in late 1978. “We see no sense in invoking the memory of the bishop’s head and the royal sword, because they symbolize the sharpness of church clashes with the government. We are for cooperation and create favorable conditions for this.”