Possible Duplicate:
When else has Mat died? (Wheel of Time, minor spoiler)
In A Memory of Light, it is revealed that:
The Horn of Valere is no longer bound to Mat, due to him having died.
However, one of the Heroes of the Horn (Artur Hawkwing himself, if I recall correctly) corrects him and indicates:
Mat's death from hanging in Rhuidean was not the death that severed the connection to the Horn of Valere.
If that wasn't when it happened, when did it? Did he die twice?