The Godfather is deservedly understood to be one of the greatest films ever made, but there were several behind-the-scenes disputes that made the filming process a particularly difficult one. The film is a cinematic adaptation of Mario Puzo's beloved crime novel of the same name, which follows the Corleone crime family in New York as Don Vito's eldest son Michael steps up to take over the business as his father grows increasingly sick. It's an extremely dark and gritty take on the genre, which has inspired countless other movies in the decades since.

One of the biggest surprises about The Godfather's production is that lead actor (and now global superstar) Al Pacino wasn't the highest-paid member of the cast. In fact, he earned less than Richard Castellano, who played a significantly smaller role. Castellano's Clemenza is a senior leader in the Corleone business who's often seen lurking in the shadows and taking out the family's most dangerous enemies. It came as a huge surprise when Clemenza was killed off-screen between The Godfather and its first sequel, but there's a specific reason for Castellano's absence related to behind-the-scenes pay disputes.

At the time of the film's release, Richard Castellano was one of The Godfather's most recognizable faces. He'd been nominated for an Academy Award for his performance in Lovers and Other Strangers and also landed a minor role in Irvin Kershner's A Fine Madness. He was undeniably a bigger star than Pacino at this point in their careers, which is why Francis Ford Coppola agreed to pay him more for a smaller role. According to The Economic Times, Pacino was paid only $35,000 for his leading role.

Meanwhile, Castellano was paid $50,000 for only 12 weeks of work, per Godfather Treasures: The Official Motion Picture Archives by Peter Cowie. This disparity in salary makes sense when considering how much of a box office draw Castellano was for The Godfather. Although Pacino ultimately became much more famous thanks to this trilogy, he was relatively unknown at the time; his name wouldn't have brought audiences to the theaters. Castellano was the opposite, and the film needed somebody like him to give it some general appeal.

The reason for Richard Castellano not returning in The Godfather Part II is somewhat disputed, but Coppola claims it ultimately came down to creative and financial disagreements. However, Castellano disputes this; he argues that he left of his own accord because he disapproved of how Clemenza was used in the film's earliest drafts. Allegedly, he didn't like the idea of his character testifying against the Corleone family and parted with the script as a result, meaning his small role in The Godfather remains the entirety of the character's legacy.

Source: The Economic Times, Godfather Treasures