They rarely meet. In fact, in NFL terms, the Patriots and 49ers are almost complete strangers, operating in different worlds - but the parallels and pulls between them run deep.
The Patriots are what the 49ers once were. And the 49ers want desperately to become what the Patriots are. Which makes the matchup Sunday night epic.
It's not merely an interconference game between the NFL's top offense and most dominant defense. This is a nationally televised pivot point for the 49ers, a chance to assert their newfound dominance and reclaim a piece of their past.