The period from March 6, 2004, to March 5, 2005, is 365 days, as February 29, 2004, has already passed. A period of 365 days contains 1 odd day. Therefore, the day of the week on March 6, 2004, was one day before the day on March 6, 2005. If March 6, 2005, was a Monday, then March 6, 2004, was a Sunday.