At the time Araphant inherited his kingdom from his father Araval, Arthedain was already in desperate straits. The Witch-king of Angmar had been beleaguering the northern lands for nearly five hundred years, and Arthedain's resistance was beginning to fail.
The one hope that Araphant had left was to renew the ancient bond with the South-kingdom of Gondor, which was at that time suffering losses itself at the hands of the Wainriders. He forged an alliance with KingOndoher of Gondor, and sealed it with the wedding of his son Arvedui to Ondoher's daughter Fíriel. Araphant's foresight failed to bring help to his kingdom, though, since Gondor itself was under sustained attack and could send no troops to his aid.
Araphant ruled Arthedain for seventy-three years. He was succeeded by his son Arvedui, who would be the last of the northern Kings.
Notes
1
The date of Araphant's birth appears only in The History of Middle-earth volume XII, The Peoples of Middle-earth. It cannot therefore be considered completely reliable.
2
The closing -phant of Araphant's name is obscure, and may not be intended to carry a specific meaning, but it perhaps derives from pant, 'fullness, totality'. The implication would perhaps be that Araphant saw himself as King of the all the Dúnedain, a title to which he did indeed have some claim. It is notable that, after many years of estrangement between Arthedain and Gondor, it was Araphant who took the first tentative - and ultimately doomed - steps toward reuniting the two realms.