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human
[Tolkien] Why did Aragorn's family not reclaim the throne before the events of Lord of the Rings?

If it was always known that Aragorn's line was the line of Isildur, what was stopping Aragorn's father or grandfather from doing exactly what Aragorn did? Why did they wait until that generation?
gpt
They did, or at least they tried to. Ancient Middle-earth history time!

The original High King of Arnor and Gondor, Elendil (the leader of the "Men" half of the Last Alliance of Elves and Men; the one who died in battle with Sauron) had two sons, Isildur and Anarion. The descendants of Isildur became the kings of the northern kingdom of Arnor, while the descendants of Anarion became the kings of the southern kingdom of Gondor. Arnor quickly fractured into three kingdoms over succession disputes: Arthedain (which in hindsight is known to have the correct claim), Cardolan, and Rhudaur. Cardolan was itself fractured and eventually destroyed by wars and plagues, while Rhudaur was corrupted by the sinister forces of the kingdom of Angmar (at the time ruled by the Witch-king, hence "Witch-king of Angmar"). Eventually, in Gondor, a King named Ondoher died without any male heirs. King Arvedui of Arthedain was married to Ondoher's daughter and the two claimed rulership of Gondor as well as Arthedain. Arvedui also claimed that Elendil had never meant for the kingdoms to be separate forever and that the heirs of Isildur (the elder of Elendil's sons) had the rightful claim to both kingdoms. However, politics intervened and the nobility of Gondor instead decided to crown the great general and recent war hero Earnil (who also happened to be a distant relative of the late King Ondoher). Shortly after this, Arthedain was destroyed by Angmar and Arvedui died (though his son survived), and in Gondor Earnil's son Earnur was the last king before the line died off (Earnur thought it would be a good idea to meet the Witch-king in a one-on-one duel in Minas Morgul). It wasn't until the great deeds of Aragorn II during the War of the Ring that Gondor accepted a northerner as a king.