Alan Greenspan, the longtime chairman of the Federal Reserve, has died at the age of 100, from complications of Parkinson’s disease.

The economist is remembered for leading the American central bank amid periods of historic U.S. economic expansion, while critics have also said his policies contributed to and exacerbated the mortgage crisis and financial crash of 2008.

Greenspan, a libertarian Republican, became the 13th chairman of the Board of Governors of the Federal Reserve System two months before the stock market crash on Oct. 19,1987, known as Black Monday. He was credited with moving quickly to alleviate investors’ fears after the crash and was instrumental in ensuring the Federal Reserve made plenty of money available to alleviate the impact on financial markets. Stocks quickly rebounded.

He was appointed Fed chair by four different presidents during his career, first by Ronald Reagan in 1987. Greenspan continued to serve as Fed chairman under presidents George H. W. Bush, Bill Clinton and George W. Bush. He steered the U.S. economy through the economic boom in the 1990s, the dotcom bubble, and the Sept. 11, 2001, terrorist attacks. His final term as chair ended on Jan. 31, 2006.

Under his leadership, the Fed fostered a distaste for regulation and promoted very low interest rates in the early 2000s — two phenomena critics say encouraged a bubble in housing prices that eventually burst with disastrous effects on the global economy.

During his tenure, and before the financial crisis began, the nation experienced one of the longest periods of economic growth in its history.

President Richard Nixon nominated Greenspan to chair the President’s Council of Economic Advisers in 1974, the first of many government economic positions he would hold. Nixon resigned as president hours after Greenspan was nominated, but he continued to serve under President Gerald Ford. Greenspan also served as a member of President Ronald Reagan’s Economic Policy Advisory Board and was a consultant to the Congressional Budget Office.

In the private sector, Greenspan served as corporate director for many companies, including Alcoa, General Foods and J.P. Morgan & Co. He also served as a member of Time magazine’s Board of Economists and a senior adviser to the Brookings Panel on Economic Activity.

In 2002, Greenspan received an honorary knighthood from Queen Elizabeth II in recognition of his contribution to global economic stability. In 2005, President George W. Bush presented Greenspan with the Presidential Medal of Freedom.

He held the position of Fed chairman from the time Reagan appointed him in 1987 until 2006, serving an unprecedented five terms under four presidents before being succeeded by Ben Bernanke.

He led the Federal Reserve through several events with major economic consequences, including two U.S. recessions, the 1997 Asian financial crisis and the Sept. 11, 2001, terrorist attacks.