In 1856, H. Meyer and Ferdinand Willius established Meyer & Willius as a private bank. Fred Meyer and Gustav Willius became partners in the bank in 1857 and the bank became known as Meyer & Willius Brothers. The bank successfully passed through the commercial crisis of 1857, but H. Meyer died in October 1857. Fred Meyer then withdrew from the firm, and the bank became known as F. & G. Willius. In 1863, Lewis L. Dunbar became a partner and the firm became Willius Brothers and Dunbar.
The notes issued by the Willius brothers acted as merchant checks. A merchant deposited funds with the firm, and they were given a like amount of small-change notes. The merchants issued these in lieu of coin when change was required for a purchase. Merchants from as far away as Mankato took advantage of this medium to alleviate the coin shortage that was induced by the war. Notes were to be redeemed before January 1, 1865.