As their sons add a new chapter to their unparalleled piece of NFL history, Jack and Jackie Harbaugh will be followed from across the country.

The warm-hearted and endlessly enthusiastic couple will celebrate their 63rd anniversary on Monday when sons John and Jim coach against each other for the third time, with Jim’s Chargers hosting John’s Baltimore Ravens at SoFi Stadium.

The Harbaughs are the only brothers to face each other as NFL head coaches. John is 2-0 in matchups, having defeated Jim’s San Francisco 49ers on Thanksgiving in 2011 and by three points in the Super Bowl the following season.