The late pontiff wrote a final letter to his biographer nine weeks before his death saying the “central motive” of his resignation was “the insomnia that has accompanied me uninterruptedly since World Youth Day in Cologne” in 2005.
Pope Benedict XVI suffered from insomnia and exhaustion, papal biographer says
Retired pope talks about his resignation, Pope Francis’ trip to Iraq
Speaking of his resignation, the retired pope recently told the Italian newspaper Corriere della Sera that “it was a difficult decision, but I made it in full awareness, and I believe it was correct.”