Pope emeritus Benedict XVI on Wednesday rejected as "simply absurd" the notions that his resignation might not be valid and that the Vatican hierarchy was now divided between loyalty to him and to Pope Francis.
"There is no doubt at all on the validity of my renunciation," Benedict said in an unprecedented letter published in the La Stampa daily, after it had written to him with questions about when he stepped down in 2013.
"The only condition for validity is that the decision be taken in full freedom. Speculation over an invalid renunciation is simply absurd," said Benedict XVI, whose Latin title is now "pontifex emeritus".
Benedict became the first pope since the Middle Ages to resign in February last year, when he said he could no longer carry on because of his declining health.
He now lives in a former monastery inside Vatican grounds and made a rare public appearance this month at a ceremony in St Peter's Basilica for the appointment of new cardinals by his successor, Pope Francis.
Born in Germany as Joseph Ratzinger, Benedict has continued wearing his papal white cassock, which has caused some confusion, but he addressed this question as simply a "practical" issue.
"Keeping the white cassock and the name Benedict are simply practical. At the time of the renunciation, there were no other cassocks available," he said.
"I wear my white cassock in a way that is distinct from that of the pope. Again, there is speculation here that has no foundation whatsoever," he added.
Benedict also said he had "a great identity of views and heartfelt friendship" with Francis and would devote himself to supporting the papacy through prayer.