Red Arrow
The sign that the Lord of Gondor sent to the Rohirrim when his land was in great need. The King of Rohan then was expected to muster troops and ride out to Gondor's aid in remembrance of the Oath of Eorl.
The Arrow was only sent north in the most perilous of circumstances. Though Gondor had been battling for many years before the War of the Ring, the Arrow had not been used to summon help from Rohan at any time during Théoden's reign. However, with the Siege of Gondor approaching, Denethor sent the Arrow north with a messenger named Hirgon. Théoden answered the summons, and brought his Riders to Gondor's aid in the Battle of the Pelennor Fields.
It was said the Arrow was red-feathered and was originally a war-treasure. The origins of the tradition of the Red Arrow are obscure, but it seems to date back to the time of Borondir, who rode north from Gondor to summon aid from the Éothéod in TA2509.
The Arrow was only sent north in the most perilous of circumstances. Though Gondor had been battling for many years before the War of the Ring, the Arrow had not been used to summon help from Rohan at any time during Théoden's reign. However, with the Siege of Gondor approaching, Denethor sent the Arrow north with a messenger named Hirgon. Théoden answered the summons, and brought his Riders to Gondor's aid in the Battle of the Pelennor Fields.
It was said the Arrow was red-feathered and was originally a war-treasure. The origins of the tradition of the Red Arrow are obscure, but it seems to date back to the time of Borondir, who rode north from Gondor to summon aid from the Éothéod in TA2509.
Encyclopedia entry originally written by Eärnil_Captain_Of_Gondor