Former Pittsburgh Steelers defensive end L.C. Greenwood, who won four Super Bowls as a member of the "Steel Curtain" defense, has died. He was 67.

The Allegheny County Medical Examiner's office says Greenwood died Sunday from undisclosed causes just before noon at Presbyterian Hospital.

Greenwood was a six-time Pro Bowler and two-time All Pro during his career from 1969-1981 and was honored on the NFL's All-Decade team for the 1970s. Famous for wearing gold cleats when he played, Greenwood joined Joe Greene, Ernie Holmes and Dwight White to form the line that served as the linchpin for the defense that helped the Steelers to four Super Bowl victories in a six-year span.

Steelers chairman Dan Rooney calls Greenwood "one of the all-time great" Steelers.