Arathorn is the son of Chieftain Arador of the Dúnedain and a descendant through many generations of Isildur himself. He first appears in annals at the age of fifty-six, seeking the hand of Gilraen as his wife. Gilraen at that time was just twenty-two years old.
The following year, Arathorn's father Arador was slain by trolls, and Arathorn took on the title of Chieftain of the Dúnedain. Gilraen bore him a son, who was given the name Aragorn. Arathorn died at the age of sixty when he was shot through the eye by an arrow while hunting orcs. After the death of Arathorn, Gilraen took their son to Aragorn Rivendell, where he was fostered by Lord Elrond.