According to papal biographer Peter Seewald, chronic insomnia ultimately led to Pope Benedict XVI’s decision to resign in 2013. 

In his last letter to the biographer — dated Oct. 28, 2022 — Benedict wrote the “central motive” for his resignation from office was “insomnia,” Seewald said according to a Jan. 27 report by CNA Deutsch, CNA’s German-language news partner. 

The pontiff, who died Dec. 31, 2022, also wrote that insomnia had accompanied him “continuously since World Youth Day in Cologne.”

The 2005 World Youth Day in Cologne took place a few months after Benedict’s election and was his first papal journey. 

The Bavarian-born Pontiff served for nearly eight more years before announcing he was stepping down — citing waning strength — on Feb. 11, 2013.

Confirming a German media report, Seewald told agency KNA that Benedict XVI had not wanted to “make a fuss about the closer circumstances of his resignation, which was justified by his exhaustion,” while still alive.

Since the rumors and speculations about Benedict's resignation have not died down, Seewald said he was obliged “to publish the decisive detail entrusted to me about the medical history of the German Pope.”

The biographer said that Benedict XVI had used strong sleeping pills.

On his trip to Mexico and Cuba in March 2012, Benedict told Seewald, he realized he must have “bumped into something in the bathroom and fallen” after waking up only to discover his handkerchief was “blood-soaked.”

After seeking medical attention, Benedict was able to continue his program. However, following the incident, the Pope’s personal physician ordered Benedict to reduce his intake of sleeping pills and stressed that he should only attend public appointments in the morning when traveling abroad.

On this account, Benedict reasoned he should make way for a new pope who would be able to attend World Youth Day in Rio de Janeiro in 2013.