Speaking on Monday at a Harold Lloyd Master Seminar for the American Film Institute Conservatory in Los Angeles, Scorsese said the idea for the movie first came to him when he was seven or eight years old, living on Elizabeth St. near Old St. Patrick's Cathedral in New York.
Most of the neighborhood was Italian, so Scorsese wondered why the church -- the first Catholic cathedral in New York City -- was named for the patron saint of Ireland.
"There must have been other people here before us," he thought.
He said a priest told him something of the area's history, including a story about the Know-Nothings planning an attack on Irish immigrants. Know-Nothings were a xenophobic, anti-Roman Catholic political party in the mid-19th century, the period during which "Gangs of New York" is set.
Scorsese said he was shocked to hear about the anti-Catholicism.
In 1970, he discovered Herbert Asbury's book, "Gangs of New York," about a period in New York City history -- from the 1840s through the infamous Draft Riots of 1863 -- when city government was thoroughly corrupt.
"It was overwhelming," Scorsese said of Asbury's book. "Each chapter could be a film."
Scorsese's friend Jay Cocks -- a former Time magazine writer who collaborated with Scorsese on the screenplay for "The Age of Innocence" (1993) -- started working on "Gangs of New York" in the 1970s.
It might surprise some to know that even a director of Scorsese's stature -- with movies such as "Raging Bull," "GoodFellas" and "Taxi Driver" on his resume -- nevertheless has trouble getting his projects made, usually because of difficulty in arranging financing.
A major reason he had trouble getting "Gangs of New York" made, said Scorsese, was that none of the places where the story happened exist any longer. He had to build New York City, circa 1846-83.
He caught a break when Oscar-nominated designer Dante Ferretti and the legendary Italian studio Cinecitta offered to build the sets for $8 million or $9 million. With the growing reliance on computer graphic imaging in the movie business, Scorsese said the designers told him "this is the last time sets like this will ever be built."
The movie took perhaps its biggest step towards becoming a reality when Scorsese's choice for the lead -- Leonard DiCaprio -- became the biggest movie star in the world after "Titanic." Scorsese had first become interested in DiCaprio for "Gangs" after the young actor had co-starred with Scorsese's frequent collaborator Robert De Niro in "This Boy's Life" (1993).
"De Niro said, 'Watch this kid. He's got a lot of talent. A lot of range,'" Scorsese recalled.
Of all the actors in "Gangs of New York," Daniel Day-Lewis is getting the best reviews. He has already been named best actor by the New York Film Critics Circle and shared the Los Angeles Film Critics Association's best actor award with "About Schmidt" star Jack Nicholson.
Scorsese said it wasn't easy getting Day-Lewis -- an Oscar winner in 1989 for "My Left Foot" who also starred in "The Age of Innocence" -- to sign on as Bill the Butcher, the villain of "Gangs of New York."
"Daniel Day-Lewis was semi-retired," said Scorsese. "He had been studying shoemaking with an Italian master. I knew he was reticent. I sent him the script ... he was very polite."
Harvey Weinstein insisted. Scorsese said the Miramax boss flew Day-Lewis to New York for a round of meetings that ended with the actor saying yes, even though -- as he later told PBS interviewer Charlie Rose -- he wasn't sure if he still "had it"
Day-Lewis' character in "Gangs of New York" is not a simple villain. Bill the Butcher genuinely believes in his anti-immigrant world view -- which would be considered merely politically incorrect today, if it were not also accompanied by the monstrous violence he inflicts to impose his values on his city.
Like earlier Scorsese movies -- "GoodFellas" and "Raging Bull" in particular -- "Gangs of New York" doesn't flinch from violence, although Scorsese provides some relief from graphic violence here and there by allowing some of it to occur outside the frame. In any case, the director insisted the movie is not about violence.
"The idea was the futility of the violence," he said, "the futility of the struggle."
Scorsese acknowledged that violence has fascinated him since childhood.
"We lived on a pitch of hysteria," he said of his family. "I thought everybody lived that way. Certainly everybody responds to it."
"Gangs of New York" has been named one of the Top 10 movies of 2002 by the National Board of Review and the American Film Institute, putting it in the top tier of contenders for Oscar gold. Fourteen people are listed as producers on the project, but only three will be able to accept the Oscar if the movie wins -- and Scorsese said he doesn't care which three get the honor.
"It's up to them," he said. "Whoever wants to go up is fine with me. I'm just glad the picture got made."
Meantime, said Scorsese, he has two "overtly religious" movies he would like to get made.
"Gangs of New York" ends with a contemporary shot of the New York skyline that features the twin towers of the World Trade Center, shot before the Sept. 11 terrorist attack -- an event that combined the elements of violence and religious fanaticism at the center of the movie.
Scorsese was editing the movie at the time of the attack. He decided to keep the shot of the towers in the final cut.
"I can't take them out," he said. "I don't want them out. Fighting, dying, the cycle of life creates the city -- it doesn't tear it down."
The Harold Lloyd Master Seminar series brings accomplished filmmakers together with AFI Conservatory students -- called fellows -- to talk about their work. The 2001-02 series has featured Tom Hanks, "Spider-Man" producer Laura Ziskin, David Lynch and Baz Luhrmann. Past seminars have featured Robert Altman, Ingmar Bergman, Francis Ford Coppola, Federico Fellini, Charlton Heston, Jack Nicholson, Sidney Poitier and Steven Spielberg.