Alan Greenspan, the influential economist who was at the helm of U.S. monetary policy during his five terms as chairman of the U.S. Federal Reserve (Federal Reserve) under four U.S. presidents, passed away today at the age of 100, as announced by his wife, according to NBC News.

Greenspan died from complications of Parkinson’s disease, as announced by his wife, Andrea Mitchell, NBC News’ Washington correspondent and chief international correspondent.

Greenspan was appointed chairman of the Fed in 1987 by President Ronald Reagan and held that position until 2006. His tenure was the second longest—four months shorter than that of William McChesney Martin, who presided over the central bank from 1951 to 1970.