Pope John Paul I, the shortest-lived pope in modern history, has moved a step closer to sainthood.

The Vatican said Thursday that Pope Francis has recognized the “heroic virtues” of John Paul I, who reigned for only 33 days before his sudden death in 1978.

His death fueled conspiracy theories that the former Cardinal Albino Luciani was murdered as part of a plot involving the Vatican bank, or perhaps committed suicide.

The move comes just days after the publication of a book that debunks the conspiracy theories. Pope Luciani: Chronicle of a Death, written by journalist Stefania Falasca, concludes that the man dubbed the “smiling Pope” died of a heart attack at age 65.

Falasca was involved in his beatification cause and had access to confidential Vatican documents, including the pope’s medical file.

Before John Paul I can be beatified, though, the Vatican still must confirm a miracle attributed to his intercession, and also a second miracle, before he can be made a saint.