EXHIBIT 16.1 ARTHUR ANDERSEN -------------------------- Arthur Andersen LLP -------------------------- 425 Walnut Street Cincinnati, OH 45202-3912 513 381 6900 March 11, 1999 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Dear Sir/Madam: We have read Item 4(a) included in the Form 8-K dated March 9, 1999 of Firstar Corporation filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, /s/ Arthur Andersen LLP Arthur Andersen LLP CJC Copy to: David M. Moffett, CFO, Firstar Corporation