House Frey
The bridge-lords of the Crossing, six hundred years rich on tolls and still hungry for standing — a Frey daughter's wedding to Lord Butterwell brings the Twins to Whitewalls.
The fuller tale
The Freys have held the Twins and its toll for six hundred years by this era, wealthy on the crossing fee alone and still visibly hungry for a standing that wealth by itself has never quite bought them — We Stand Together sits on their banner with an earnestness that later history would treat considerably less kindly.
That hunger is what brings the Twins to Whitewalls at all: a Frey daughter's marriage to Lord Ambrose Butterwell gives the family a seat at a grander table than tolls alone usually earn them, and the wedding draws half the family's ambitions along with the bride.
Somewhere in that feast, unnamed but unmistakable to anyone who knows what comes later, sits a four-year-old Frey boy — the same child who will grow up to become Lord Walder Frey, presiding decades hence over a wedding of his own with far less hospitable table manners than his family's motto currently advertises. It is the saga's quietest joke, and its cruelest, aimed entirely at readers who already know the ending this child does not.
The page and the screen
The Whitewalls wedding and its Frey connection belong to The Mystery Knight, unadapted as of this writing; the dramatic irony of the toddler in the crowd currently exists only for readers of the novella, with no screen equivalent yet filmed.