Being acquired by Aon Corp. will bring Hewitt Associates Inc.'s 70-year run as an independent company to an end.

Ted Hewitt launched the company in 1940 under the name Edwin Shields Hewitt & Associates as a Lake Forest, Ill., insurance brokerage.

In 1959, Hewitt opened an office in Minneapolis, its first outside Illinois. The office it opened in 1974 in Toronto was its first beyond the United States. It expanded beyond North America with the 1985 opening of offices in Paris and in St. Albans, England, just outside London.

The company became Hewitt Associates Inc. when it went public in 2002. By then, Hewitt had become a benefit consulting and outsourcing giant with more than $1.7 billion in revenues and 14,600 employees. At the time, it was the nation's second-largest benefit consultant as ranked by Business Insurance.

Much of Hewitt's growth has been organic, but several key acquisitions aided its growth.

Its 2002 acquisition of Bacon & Woodrow Ltd. in London made Hewitt a major player in the U.K. benefits consulting market, while its 2004 purchase of Irvine, Calif.-based Exult Inc. significantly expanded the breadth of its outsourcing services.

Last year, Hewitt generated more than $3 billion in revenues and had more than 23,000 employees in 32 countries.

Aon, whose origins go back to 1982, when Ryan Insurance Group merged with Combined International Corp., grew through acquisitions.

It acquired storied names in insurance brokering such as Alexander & Alexander Services Inc.; Miller, Mason & Dickenson; Rollins Burdick Hunter Co.; and, more recently, Benfield Group Ltd., the U.K. reinsurance broker it acquired in 2008.

Today, Aon is ranked as the world's second-largest insurance broker. In all, Aon has 36,000 employees operating from 500 offices in 120 countries. Last year, it generated about $7.6 billion in revenues.