Ever since Benedict XVI announced his resignation on Feb. 11, 2013, cardinals and others have speculated on the main reason for his decision to resign. Today, his German biographer, Peter Seewald, confirmed that nine weeks before he died, Benedict, in his last letter to him, revealed that insomnia was the “central motive” for his resignation.

The news first appeared in the German magazine Focus. It said that in the letter on Oct. 28, Benedict mentioned “the insomnia that has accompanied me uninterruptedly since World Youth Day in Cologne.” Mr. Seewald confirmed the news to the German Catholic News Agency (KNA).

World Youth Day took place in Cologne in August 2005. Benedict was elected pope on April 19, 2005.

In the letter, Benedict wrote that the “strong remedies” prescribed to him by his personal physician at the time had initially worked and guaranteed his “availability” as pope. However, he said the medicines soon “reached their limits” and were “less and less able to ensure” his continued service as pope.

Finally, the pope recalled that during his trip to Mexico and Cuba in March 2012, there was a serious incident. The morning after the first night of the visit in Mexico, Benedict revealed that he had reached for his handkerchief to find that it was “totally soaked with blood. I must have bumped into something in the bathroom and fallen.” He said a surgeon “thankfully” managed to treat the matter in such a way that the injuries were not visible.

The story of Benedict’s fall in his bedroom in Mexico was known among journalists in Rome sometime after the visit, including the author, but not in this detail.

After this incident, Benedict wrote that his new personal physician had urged a reduction in sleeping pills and insisted that he only be allowed to appear in public on mornings during future trips abroad. According to Benedict, it was clear to him that these medically justified restrictions “could only apply for a short time.”

Read on.