Modernist poetry refers to poetry written, mainly in Europe and North America, between 1890 and 1950 in the tradition of modernist literature, but the dates of the term depend upon a number of factors, including the nation of origin, the particular school in question, and the biases of the critic setting the dates. The critic/poet C. H. Sisson observed in his essay Poetry and Sincerity that "Modernity has been going on for a long time. Not within living memory has there ever been a day when young writers were not coming up, in a threat of iconoclasm."