By STEVE SMITH

Credit for inventing the string quartet tends to be laid at the feet of Joseph Haydn, that industrious, fecund genius whose life’s work counts among the crowning achievements of the 18th-century Austrian Empire. Credit for intuiting that the medium could be opened wider - in a sense reinventing the string quartet as a vehicle of limitless stylistic breadth - belongs to the violinist David Harrington, who founded the Kronos Quartet in 1973.

Today the quartet - currently Mr. Harrington, the violinist John Sherba, the violist Hank Dutt and the cellist Jeffrey Zeigler - spends some five months a year on the road, playing in concert halls, nightclubs and at festivals. It has sold more than 2.5 million recordings from a discography of nearly 50 albums, most of them on the Nonesuch label. The latest Kronos disc, “Rainbow,” a collaboration with the Afghan rubab player Homayun Sakhi and the Azerbaijian singers Alim and Fargana Qasimov, comes out in March on the Smithsonian Folkways label as part of a superb Central Asian series sponsored by the Aga Khan Trust for Culture.

Mr. Sakhi and the Qasimovs will be among the guests joining Kronos in four concerts at Carnegie Hall in New York in March . The events offer a tour through the far-flung terrain Mr. Harrington and his colleagues have mapped: a celebration of the group’s 30-year relationship with the composer Terry Riley on March 11, a concert featuring electronics and toys on March 12, an Arctic-theme program March 13 and a collaboration with Central Asian and Korean artists on March 14.

Mr. Harrington was spurred to form Kronos by a radio broadcast of “Black Angels,” a searing musical response to the Vietnam War by the American composer George Crumb. Encountering, in 1973, Mr. Crumb’s sophisticated, phantasmagorical mix of sounds inspired Mr. Harrington - who had avoided the draft by joining a Canadian orchestra - to conceive of a group that would play new quartet music with similar presence and urgency. The first Kronos commission went to Mr. Harrington’s high-school composition teacher, Ken Benshoof, whose “Traveling Music” famously cost Mr. Harrington a bag of doughnuts.

“I think the reason you and I are talking today is because that piece was so good, and because that relationship, which started when I was about 15, was so enjoyable and so thrilling,” Mr. Harrington said. “When we got out there to play his Piano Quintet when I was 15, it felt like this music belonged to me and belonged to those of us who were performing it, and nobody else had ever heard it, and it was so fun.”

The Kronos Quartet went on to commission more than 650 new compositions and arrangements at the latest tally, including major works by Mr. Riley, Steve Reich, Philip Glass, John Adams, Sofia Gubaidulina, Henryk Gorecki, Tan Dun and Osvaldo Golijov. Had Kronos achieved nothing more, that body of work would assure it an honored place in the chambermusic annals.

When the Kronos Quartet hit its stride during the late ‘80s, its concerts were powerful, absorbing affairs not despite their extra-musical trappings, but in part because of them. On its Nonesuch albums, the group promoted a hip, new take on contemporary music: much of it melodic and rhythmically driving, nearly all of it fresh and vital. In concert, hearing Kronos play the latest pieces by composers like Mr. Riley, John Zorn and Istvan Marta - amplified and accompanied with suitably moody lighting - was an intense, heady experience that could move you to the core.

Surprisingly, Kronos has spawned few imitators. But the Kronos influence is everywhere. Iconoclastic artists of all musical persuasions mingle and collaborate , and no one is surprised when alternative-rock acts like Sufjan Stevens and Dirty Projectors work with chamber ensembles and orchestras. Composers who start out playing rock, hip-hop and electronica apply those influences in their concert works, then run out to play in their own bands.

Those developments may have been inevitable, but Kronos got there first . In intuiting the shape of things to come with his reimagined string quartet, Mr. Harrington had a hand in inventing the future.