In this passage from the Iliad, near the climax where Achilles kills Hector, Priam is trying to persuade his son Hector to come back into the safety of Troy and not face Achilles which would be certain death. He recounts the awful things that will happen if Hector dies. He describes himself as on the threshold of old age. This meant something else in Greek than Iit would to us. Plato has used it in the sense of the threshold between old age and death, that is the end of old age. Here it probably means the threshold which is old age, that is old age is the theshold between life and death.
And, as well, have pity on me wretched as I am while I still have my wits, an ill-fated man whom the father, son of Kronos, Zeus will destroy with a dreadful fate while I am on the threshold which is old age when I have seen so many horrors – my sons destroyed, my daughters dragged away, my chambers ransacked, baby children thrown on the ground in dreadful war, my son’s wives dragged off by the murderous hands of the Achaeans. And as for myself last of all savage dogs at my front door will tear at me when someone has struck me with sharp bronze or taken my life from my limbs by striking me, those dogs that I raised in my house, table dogs to guard my doors who, when they have drunk my blood, will lie mad in heart in the doorway.