Letters reveal only one side of a truly remarkable story
There is one missing piece of the jigsaw in the correspondence between the Pope and Anna-Teresa Tymieniecka that would help understand the depth of the relationship. Her original letters to the pontiff and replies to his letters have not been revealed, meaning we have to piece together the relationship from one side of the exchanges.
After the pair met in 1973, they began writing letters that were initially formal in tone. The then Archbishop of Krakow writes: "Dear Professor Tymieniecka...", before going on to discuss some of the complex philosophical matters they had been in dialogue about.
Both the future Pope and Ms Tymieniecka had much in common: they had both survived the Nazi occupation of Poland and now lamented the totalitarian communist regime that gripped their homeland. It was known that all letters Cardinal Wojtyla sent from his residence in Krakow were likely to have been read by the secret police.
A year later the letters had a tone of intimacy. Writing from Rome, where Cardinal Wojtyla spent more than a month in the autumn of 1974, he said her letters were "so meaningful and deeply personal". He noted he had taken the letters to Rome so he could answer them "without using the mail", likely to be a reference to the communist interception of post.
Towards the end of the same letter, he adds: "There are issues which are too difficult for me to write about." Without access to the full letter, it is impossible to know whether he is referring to the complexity of the philosophical discourse or something more personal.
In the late 1970s Wojtyla gifted to Tymieniecka a brown scapular which had been gifted to him by his father at the time of his First Holy Communion. He wrote that knowing she had the scapular allowed him to "accept and feel you everywhere in all kinds of situations, whether you are close, or far away".
In 1976, while attending a conference in the US, Cardinal Wojtyla stayed with Ms Tymieniecka and her family at her summer house. It was a paradise for the Polish cleric: he was able to enjoy walks in the countryside and spend quality time with his dear friend. After returning from that trip, he wrote to Ms Tymieniecka describing her as a "gift from God".
"If I did not have this conviction, some moral certainty of grace, and of acting in obedience to it, I would not dare act like this," he wrote.
The relationship suffered a rupture in 1978. Immediately after his election as Pope, Ms Tymieniecka rushed to publish a book that they had been working on. Believing the tome to be unfinished, the Pope was distraught and the Vatican fought a legal battle on his behalf to halt publication. Ms Tymieniecka told friends she felt betrayed.
But the warmth evidently returned. A couple of years later, when the pontiff was wounded in an assassination attempt, Ms Tymieniecka dropped everything to be at his bedside in Rome.
The correspondence continued as the Pope's health declined with the onset of Parkinson's disease in the early 1990s. She visited him regularly and sent him pressed flowers from her summer home, a clear reminder to the pontiff of the time he had spend there in 1976: "I am thinking about you, and in my thoughts I come to Pomfret every day."
It was a friendship that endured to the end. As the Pope lay dying in his private apartment in the Vatican in April 2005, Ms Tymieniecka was one of the few close friends admitted to see him.