A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Atarah al'Norahn
His grandmother was Lady Nelein, whose temper even Aedmun tiptoed around.
The House of Matherin is not large enough to count towards gaining the Rose Crown, but Elayne makes a point of visiting many of the Houses that are bound to her by blood or oaths. Elayne thinks to herself that while House Matherin is not large or strong, it is old.
The manor of House Matherin lies just over twenty miles from the River Erinin. Inside, Elayne sees a wall hanging of women from House Matherin handing a sword to the first Queen of Andor, an event that Matherin treasures. Elayne is not sure whether this event ever took place.
When Aedmun learned that there were contenders for the throne other than Elayne, he set off for Caemlyn straight away, not even waiting for spring. When Elayne visits House Matherin, she is told that he might be halfway to Caemlyn by now.
(Reference: Crossroads of Twilight, Chapter 10)