Friday’s news that Lloyd Blankfein would retire from Goldman Sachs as soon as the year end was a surprise to almost everyone.

He will have served 12-years as Goldman’s chief executive, longer than anyone else except Sidney Weinberg (who retired in 1966), and is one of the longest-serving CEOs among today’s major banks. Blankfein replaced Hank Paulson as CEO in 2006, having transformed the firm’s fixed income, currency and commodities (FICC) division into a trading powerhouse that was arguably Wall Street’s most dominant player.