Henry W. Marsh dropped out of Harvard to seek his future in Chicago. The Great Fire of 1871 had wiped out most insurers and Marsh saw opportunity for insurance brokers that could distribute great risks across many firms. Almost upon arrival, his ambitions were bigger than the new company he joined. Marsh wanted to open an office in New York. Then he set out to win U.S. Steel, the world's first billion-dollar corporation. Colorful, urbane, high living, and audacious, Marsh was the kind of man who would book a transatlantic passage so he could pitch AT&T's Theodore Vail aboard ship. On Vail's return voyage, there was Marsh again. He got the business.
Donald R. McLennan of Duluth, Minnesota, became his family's sole support at age 14. In business life, his intense competitiveness took the form of thoroughness. McLennan was all diligence, researching insurance clients' operations until he knew as much as the owners. During 1901, while Marsh was pursuing U.S. Steel, McLennan was mastering the intricacies of railroads, winning one line after another. He spent weeks at a time inspecting every property along thousands of miles of road — a man who believed in research, and in seeing for himself.
When the two men merged their firms in 1904, the new company was the largest insurance agency in the world with annual premiums of US$3 billion — and it was only the beginning.