In 1971 a black director made a film with black actors. It launched a new genre known as 'Blaxploitation' movies which brought pride - and disapproval - to a hitherto angry minority and made 'zillions' for its maker
There were assertive black politicians and hugely popular musicians, but until 1971 there were no parts for virile, black actors. And then there was Sweet Sweetback's Baadasssss Song. It changed the face of black films.

Known as "blaxploitation", more than 200 black action films were produced between 1971 and 1975, and satisfied a craving among black audiences who wanted to see more aggressive and sexual black protagonists in films. It precipitated an extraordinary outpouring of previously repressed emotions. Just about the only film that black audiences had been offered since 1915 was DW Griffith's film The Birth Of A Nation, which was bloated with grotesque black stereotypes. The emergence in the Sixties of actors such as Harry Belafonte and Sidney Poitier did at least give their characters an aura of dignity.

In 1968, the murder of Martin Luther King broke the impetus of the civil rights movement, and increasingly militant black nationalist groups such as the Black Panthers emerged from the political background. So too did Sweetback. Today, its director, Melvin Van Peebles, describes it as "the movie I wanted to see".

The story tells of a man who rescues a young black, Sweetback, from an act of police brutality and is consequently chased through the black districts of Los Angeles, eventually escaping over the Mexican border. Sweetback is, initially, apolitical, but over the period of the chase he becomes enlightened.

The character is almost mute throughout the film because, according to Van Peebles, "I wanted Sweetback to be an 'everyman'. By him not talking, the audience put their interpretation on what he was doing."

The film was technically groundbreaking, especially in its use of superimposed images. The director also showed foresight in persuading an unknown group, Earth, Wind and Fire, to perform his soundtrack. Van Peebles called the film a "song" because he "thought of it as an opera".

The film was a huge financial success and the director admits: "I made a zillion dollars." But he was criticised for allowing Sweetback to have a prodigious libido, a quality his detractors believed was a resurgence of an old black stereotype. They underestimated Melvin Van Peebles, who rejects this accusation: "I stood a lot of these stereotypes that we'd been whipped over the head with, I took them and stood them on their end. Like judo, you take the momentum of their energy and use it against them".

The film ends with the message: "A baad ass nigger is coming back to collect some dues."

Although Van Peebles did not make a sequel, partly due to the jealous contempt of the white film industry, characters similar to Sweetback did appear in droves, in films such as Shaft, Superfly, Across 110th Street, Black Belt Jones, and The Mack. Today, Van Peebles admits that Sweetback is the direct father of blaxploitation.

Sometimes morally ambivalent, the films often centred on the lives of pimps and drug dealers. They were criticised for doing so, but, as Nelson George points out: "Why is The Godfather acceptable and not Shaft?"

Rudy Ray Moore, with his film Dolemite, provided some comic relief from the constant combative posturing in the other black films. Although a woman whispers "You're the only man that really blows my mind" seductively to him, Rudy Ray Moore sensed the humorous side of the films and created ludicrous characters and absurd situations.

Dolemite, along with the other cartoon-like characters, dresses in the most extreme fashions of the day, and the dialogue is peppered with such phrases as "Right on", "Can you dig it?" and "That's mighty black of you". Today, he admits that "I didn't make the film with any political thing in mind. I made a film that would please, primarily, the black audiences in this country."

The link between that period of the 1970s and the rap era of today is strong, as Darius James, the author of That's Blaxploitation, explains: "Yesteryear's Superfly cult fathered today's brood of gun-loco, inner- city cowboys." Both Rudy Ray Moore and Melvin Van Peebles have been credited with initiating early forms of rapping, while the rapper Foxy Brown has adopted her pseudonym from the title of a black film made in 1973. The mother of the rapper Tupac Shakur was a member of the Black Panthers.

Today, the black films of the Seventies are experiencing a renaissance. Rudy Ray Moore, who recently appeared in a music video with the rapper Busta Rhymes is making a film called Faking The Funk with Pam Grier, the most famous black heroine of the Seventies. The director, John Singleton, who was responsible for Boys 'N' The Hood, is filming Shaft Returns, and Don Cheadle is remaking Cleopatra Jones. Ironically, just as white directors and producers in the 1970s wrestled control of the genre, so Quentin Tarantino has modelled his new film, Jackie Brown, on the black films of the 1970s. Like those white directors and producers, he too disingenuously describes his film as "a black film".

'Sweet Sweetback's Baadasssss Song', 'Dolemite' and 'Thug Immortal' are released on video for the first time in Britain by Xenon on 26 February.

Melvin Van Peebles and Rudy Ray Moore both appear at the Baadasssss Ball on 24 February at the Cafe de Paris, London WC2 (0181-245 7628).