Al Pacino was considered too short, Marlon Brando was required to do a screen test, and director Francis Ford Coppola was almost fired.

The director and cast of The Godfather reminisced on Saturday in a 45th anniversary reunion in New York about the trials, perseverance and inspiration that resulted in the Oscar-winning Mafia movies.

Coppola, Pacino, Robert De Niro, Diane Keaton, James Caan, Talia Shire and Robert Duvall watched back-to-back screenings of The Godfather (1972) and The Godfather: Part II (1974) along with an audience of 6,000 on the closing night of the Tribeca film festival.

“I haven’t seen these movies for years,” said Coppola. “I found (watching) a very emotional experience. I forgot a lot about the making of it and thought about the story, and the story used a lot of family and my personal stuff.”

The two films won nine Oscars and their tale of how an orphan from Sicily emigrated to the United States at the turn of the 20th century and formed the Corleone crime family became movie classics.

But the film had a less than auspicious start. Coppola recalled that Hollywood studio Paramount wanted to set the movie in the 1970s and make something "cheap and quick".

Coppola was almost fired several times and met stiff resistance to the casting of both Pacino as Michael Corleone and Brando as the titular Godfather.

Brando, who died in 2004, had made several box-office flops after a stellar career in the 1950s and had a reputation for being difficult.

“I was told (by studio executives ) that having Brando in the film would make it less commercial than having a total unknown,” said Coppola.

The studio later agreed “if Marlon will do a screen test and do it for nothing and put up a million dollar bond that he wouldn’t cause trouble during the production”.

More trouble

Brando created the rasping voice, jowly cheeks and oiled hair for Corleone in the screen test. Yet three weeks into shooting, there was more trouble.

“They (the studio) hated Brando. They thought he mumbled and they hated the film . . . It was very dark,” said Coppola. Brando went on to win an Oscar for his performance.

Newcomer Pacino had to screen test "countless times" for the role of Michael, the college-educated son who takes charge of the Corleone business of casinos, gambling and racketeering. Studio bosses though he was too short and wanted to cast Robert Redford or Ryan O'Neal.

Yet Coppola persevered because “every time I read the script, I always saw his (Pacino’s) face, especially in the scenes in Sicily”.

Pacino said he originally wanted the part of the hot-headed son, Sonny, and thought Coppola “was really nuts” about wanting him to play Michael.

“I thought this is either a dream or a joke . . . and then started the whole trial of them not wanting me and Francis wanting me,” recalled Pacino. The film launched his career as one of the most honoured actors of his generation.

Luck played a part in the creation of some of the most memorable scenes in the two films. The revelation by Corleone's wife Kay (Keaton) that she had aborted their baby because of horror over her husband's criminal activities was suggested by Talia Shire (Connie).

And the cat Brando cradles in the opening scene of The Godfather, making for a stark contrast with his intimidating presence, was a last-minute addition.

“I put that cat in his hands. It was the studio cat. It was one take,” said Coppola.