What is the time period or literary period in "The Knight" by Adrienne Rich?

"The Knight" was first published in Rich's 1963 collection of poems entitled Snapshots of a Daughter-in-Law: Poems, 1954-1962. Although this collection of poems was first published in 1963, the poems therein, including "The Knight," were written, as the title indicates, between 1954 and 1962.
In terms of literary periods, the period beginning in 1945, after World War II, is usually described as the postmodern period. Postmodernism is characterized by a critical attitude towards assumed and traditional moral, social, and cultural viewpoints, including traditional attitudes towards gender. In the poem itself, Rich challenges the traditional viewpoint that male weakness and vulnerability is to be repressed, and, if not repressed, ridiculed. The exposed weakness of the eponymous knight in the poem is portrayed as a positive, rather than a negative. In this way, "The Knight" might be considered a postmodern poem.