1. Thomas Hardy's age in 1898, the year his first volume of poetry (Wessex Poems) is published: 58. This unusual late debut makes him to a certain extent the Modernists' contemporary. His subject matter, moreover, is an old man's through and through: poems about friends and lovers dying, not being able to change things about yourself, rain on graves, etc. But in the figure of Hardy, age is not associated with a failing of powers (as it would have been in Tennyson or Swinburne) or even with a development or consolidation of old achievements (as with somebody like maybe Browning), but with a new aesthetic and a fresh start: Hardy, having experienced enormous disappointment and pain, is now finally ready to write and publish poetry. (Slight problem with this theory: Eliot didn't really like Hardy's work, and Yeats started publishing before him, so his example might not have meant much to them. Who did like him? Marianne Moore? But she's got to be one of the sprightliest of the Modernist bunch.)
2. The poets of the 1890s (especially Ernest Dowson and Lionel Johnson) were seen as dissolute, drunken messes who wasted their talent and died unnecessarily early deaths — i.e., as cautionary tales about what the post-romantic/aesthetic embrace of youth could lead to. Cf. Yeats' "The Tragic Generation," and Eliot's remarks on these people in the back of Inventions of the March Hare (quotes t/k?).