When Marvin Lewis walks off the field Sunday at M&T Bank Stadium in Baltimore, all signs point to his run of 15 years, 247 games and seven postseason appearances in Cincinnati coming to an end. The second-longest tenured head coach in the NFL could move on from the Bengals to explore other opportunities. If it plays out that way after his meeting with Mike Brown on Monday morning, what’s left in his wake at 1 Paul Brown Stadium will be one of the most complicated legacies in the 50-year history of this franchise. Fully understanding it requires a flashback to his introductory press conference in 2003. Judging Lewis by his own words that day unearths an overwhelming success and unequivocal failure. Lewis’ hiring was about more than sports, it was a civic event. Mayor Charlie Luken attended and offered Lewis a key to the city. “It opens the vault,” Luken said that day, “but the vault is empty.” The franchise was empty. A laughingstock coming off the worst decade in the history of professional sports. Lewis accepted what was widely considered the worst job available.