Could someone briefly explain at least two factors that influenced Yeats’ writing of “The Second Coming”?

I think that the reality that enveloped Europe after World
War I represented on factor that influenced Yeats' writing. Emerging from the war, Yeats
and many other thinkers were convinced that the structures and institutions that
supposedly provided a sense of totality in the lives of individuals were the same forces
that brought on the war, bringing unprecedented death, suffering, and destruction.  This
is the first stanza of the poem of the images such as "the widening gyre" and the
twisted relationship between the "falcon" and "falconer."  It is this portion of the
poem that makes Yeats mournful for what was endured and the sense of fragmentation,
"things fall apart," is an excellent representation of Europe after the First World
War.

The second stanza represents Yeats' fears of the
future.  As bad as the First World War was for Europe, Yeats is convinced that the
fragmentation present is going to actually be worse for Europe.  It is going to be a
situation where some "rough beast" will be born.  Yeats was concerned with the overthrow
of the Czar in Russia and the Communist government that emerged from it.  At the same
time, Yeats is almost prophetic in writing about the European fascism that will take a
hold of Europe in the 1930s in the form of Mussolini, Stalin, Franco, and, of course,
Adolf Hitler.  In the second stanza, the fragmented reality of Europe and the lack of
any totality is what influences Yeats into constructing a vision of the future that is
far worse than the despair of the present.