The northern Italian diocese where he was born is gathering testimony about his life in hopes of persuading the Vatican that he should be made a saint, a process that can take years or even decades.
The Rev. Giuseppe Bratti, secretary to the bishop of Belluno-Feltre, said the testimony includes increasing accounts of possible miracles that faithful attribute to John Paul I.
The bishop, Monsignor Vincenzo Savio, said Sunday that a priest in Rome has been named as postulator, the person who formally oversees the cause for possible sainthood.
The Vatican must certify that a candidate has saintly virtues and has performed a miracle before beatification, the last formal step before possible sainthood. After beatification, a subsequent miracle is needed for canonization.
Bratti said Luciani's writings during his life have been gathered and will be submitted as part of the case for sainthood.
Last year, Italian state TV reported that the signatures of some 300,000 Roman Catholics had been gathered in a sign of support for sainthood for Luciani.
John Paul I was 65 and apparently in good health when he was elected pontiff on Aug. 26, 1978. He quickly won over his flock with modesty and good humor, earning the nickname "the smiling pope."
His unexpected death of a heart attack sparked a rash of dark theories.
Relatives have questioned the Vatican's account that a priest found Luciani dead in bed. A niece has been quoted as saying she was told a nun found him dead at his desk.
Some theories have claimed foul play, speculating about power struggles between church conservatives and liberals, an Italian banking scandal involving the Vatican, and even a poisoning plot. The Vatican said he died of natural causes.
Elected by his fellow cardinals to succeed Luciani in the papacy was a middle-aged Pole, Karol Wojtyla, who took the name John Paul II. His papacy is one of the longest in history.