The Hundred Companions were a group of one hundred thirteen young male Aes Sedai from the Age of Legends who were very vocal supporters of Lews Therin Telamon's plan of attacking the Bore directly and sealing the Dark One in his prison.
The Heroes of the Horn are the great heroes of the Pattern, bound to the Horn of Valere. They are summoned to battle to fight for the Light. Sometimes the Wheel adds to their numbers, however it is unknown if heroes can be lost from the ranks.
It is known that Horn also summons approximately hundred or so heroes which are bound to the wheel. The number strikes to me as coincidental?
Is it stated if the companions were actually Heroes of the horn (or some were)?