William Butler Yeats decided that he wanted to be an artist and poet after completing high school (he studied in London and Dublin). He left not too long abter because he decided to concentrate on his poetry.
Yeats was interested in many kinds of folklore and mythology, and his early works he often wrote on pagan and Irish themes. But it's generally considered that as Yeats grew older his poetry become more refined and perfected, and his later works are aknowledged to be his best: in 1923, Yeats won Nobel Prize.
