Well, "In Memory of W.B. Yeats" is about as traditional as an elegiac title can be (and this is an elegy, a poem written in memory of a deceased person). It brings to mind another uber-famous (and uber-long) elegy called In Memoriam, A.H.H., written by Tennyson about his friend who passed away.
If you've read what we have to say in our "Summary" section, you'll immediately see the irony in this move: Auden's title may be traditional, but his poem is anything but. He's shaking things up stylistically, which is perhaps why he chooses to ground us right away by directing our attention to the object of the poem, William Butler Yeats. Yeats was a poet, playwright, and important political figure in the late 19th and early 20th century. If you're interested, you can find out more about him by checking out our guides on his poetry. Here are a few: