Argeleb I was the seventh King of Arthedain. During his reign the numbers of the Dúnedain in the kingdoms of Rhudaur and Cardolan were so diminished, that he tried to reunite the three kingdoms, and again have one cohesive state. He wished to claim kingship over all of Arnor himself, but he was met by resistance and eventually war. Argeleb I, and the kings who came thereafter, claimed themselves the lords over all of Arnor so they began taking their names with the prefix of 'Ar' to signify this fact.

The numbers of the Dúnedain were especially reduced in Rhudaur, where power had been seized by an evil lord of the Hillmen who was secretly allied with Angmar. Rhudaur resisted Argeleb's claim to the throne of Arnor fiercely, and with the help of Angmar, declared war against the other two kingdoms. Argeleb fortified the Weather Hills and the areas around them, but battle ensued, and Argeleb was slain.



Argeleb I reigned from TA 1347 until TA 1356. He was succeeded by his son Arveleg I.