Alan Greenspan, seen in October 2007, served as the chairman of the US Federal Reserve for nearly 20 years, under four presidents. (Photo: AFP)

WASHINGTON — Alan Greenspan, the longtime United States Federal Reserve (Fed) chief who presided over an unprecedented period of American economic expansion but was later faulted for failing to rein in markets ahead of the 2008 global financial crisis, has died.Greenspan -- who died Monday at age 100 -- guided the world's biggest economy through a stock market crash in 1987 as he first took up his post, the Mexican and Asian financial crises, the dotcom boom and bust, and the attacks on Sept 11, 2001.

A native New Yorker who excelled at math as a child but initially studied music before pivoting to economics, Greenspan spent decades in the inner circles of power in Washington, ultimately leading the Fed for presidents of both political parties.

Greenspan was even hailed as the greatest central banker the world has ever known, winning glowing praise for his steady hand and cool demeanor.

Supporters especially admired his willingness to cut interest rates and keep them low even as unemployment rates fell -- which conventional wisdom and his own early beliefs said would cause inflation to spiral out of control.