Poetry is often defined in mysterious ways. The most common belief one will hear in a creative writing program is that it’s all about “feelings.” Students are challenged to write about their personal experiences, then workshop them with a group in a validating way.
This idea would have been utterly alien to Virgil, Shakespeare, and Tennyson. The great poets of history learned their craft in ways more like students of science than English today, with a heavy emphasis on the nuts and bolts of literary technique.