A long line of priests, nuns, deacons, relatives and fans wound its way into the crypt beneath the altar of St. Patrick's Cathedral. Their mission: the canonization of Archbishop Fulton J. Sheen, one of the first priests to use TV to educate, inspire and even convert.

Twenty-five years after the archbishop was buried in the crypt, a Mass was celebrated in his honor. The people who gathered at St. Patrick's on Thursday wanted to persuade the Vatican to declare the archbishop a saint.

''It's like a kickoff, so to speak, with a liturgy,'' said Msgr. John E. Kozar, the national director of the Pontifical Mission Societies in the United States, which includes the Society for the Propagation of the Faith, a group led by Bishop Sheen, as he was known. ''It's a public announcement in the most fitting way.''

Bishop Sheen, whose father owned a hardware store in Illinois, was ordained in Peoria in 1919. Three decades later he pioneered religion on television with weekly broadcasts of a half-hour program, ''Life Is Worth Living,'' which attracted more than 25 million viewers and higher ratings than Milton Berle.

He appealed to television viewers of many faiths and was respected by church officials for his ability to convert people -- including Henry Ford II -- to Catholicism. After winning an Emmy Award, Bishop Sheen credited his four writers: Matthew, Mark, Luke and John.

Bishop Sheen died in 1979 at his home on the Upper East Side of Manhattan at the age of 84.

Twenty years later, the Rev. Andrew Apostoli, a Franciscan friar Bishop Sheen had inspired as a boy, began the push for canonization.

In 2002 the Vatican declared Bishop Sheen a servant of God, a step that allowed his supporters to make a case for sainthood. The process is rigorous, requiring a detailed report about his life, teachings and writings, and the documentation of at least two miracles attributed to him.

The Mass at St. Patrick's on Thursday, marked the 25th anniversary of Bishop Sheen's death, but it was also was an effort to build grass-roots support for his canonization.

''The Mass is meant to be a public manifestation of the public enthusiasm for Archbishop Sheen, a showing of devotion, which could build more enthusiasm,'' said Msgr. Richard Soseman, who is serving as the delegate for the canonization cause for the Rev. Daniel R. Jenky, the bishop of Peoria. Supporters of Bishop Sheen say that starting the canonization effort in Peoria, where he was ordained, rather than in New York will improve their chances of success because more canonization campaigns originate in New York.

The Rev. John J. Coughlin, an expert on Roman Catholic Church law at the University of Notre Dame, said the canonization process often involves a certain amount of political jockeying making it difficult to handicap the campaign. Bishop Sheen attracted a large and fervent following, in part because he was able to make complex theological concepts understandable, Father Coughlin said. But, he added, it would be hard to predict the influence of that popularity on the Vatican.

Before television, Bishop Sheen became well-known on the radio. He was on ''The Catholic Hour'' on NBC in the 1930's.

In his show, first on the DuMont Network and later on ABC, Bishop Sheen delivered religious instruction, advice and political opinions in an energetic and conversational tone. He was anti-communist and stirred controversy with his support of Franco's fascists as a counterweight to communism. He also favored corporal punishment in schools and opposed the psychoanalysis of Freud.

His supporters are now compiling testimony on possible miracles that could be attributed to the archbishop. Joan Cunningham, 77, a niece of the archbishop's who lives in Yonkers, said that the recovery of a sick young boy may have been one such miracle.

At the archbishop's crypt on Thursday, his admirers knelt to pray on his prie-dieu, trimmed in red and gold velvet, and ran their hands along the etching of his name on his tomb. Bishop Sheen is buried next to Cardinal Terence Cooke and near Cardinal John O'Connor.

Standing in the crypt, Monsignor Soseman said he was encouraged by the large turnout but reluctant to predict whether Bishop Sheen might become a saint.

''We'll all know,'' he said, ''in anywhere from two years to 50.''

Photos: Visitors to the crypt beneath St. Patrick's on Thursday, before a memorial Mass on the 25th anniversary of Bishop Fulton J. Sheen's death. (Photo by Susan Farley for The New York Times); Bishop Sheen in 1979. (Photo by Fred R. Conrad/The New York Times)