The Northwestern Mutual Life Insurance Company was incorporated by chapter 129 of Laws of Wisconsin for 1857 (though it began business in 1858).

The evidence

• “In 1858 the Northwestern Mutual Life Insurance Company, now at Milwaukee, one of the best known of the large life insurance companies, began business at Janesville. It was incorporated by chapter 129 of Laws of Wisconsin for 1857. The incorporators were mainly from Janesville, though some were from Beloit and also some from outside the county.”

  1908-brown-rock-county/26-history-of-janesville.md, Vol. 2, PDF p. 42 / book p. 555

  Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.

  Grade A: Found on a page of one of our sources