W. H. Auden wrote "Spain" in 1937, about one year into the Spanish Civil War. Hitler was on the move across Eastern Europe and Fascism was spreading its cloak when, on July 18, 1936, Spain erupted into civil war which put Fascist Franco in power as the head of Spain.
Auden laments the tragedy going on in Spain in this poem. The first six Stanzas are devoted to describing the ancient and then not-so-ancient past from the opening of Chinese trade routes because of Marc Polo to the invention of clocks that led to navigation and exploration to the Renaissance, Reformation, Enlightenment and Industrialization. Each of the six stanzas is presented as a separate time fragment.
Auden then switches to a nondescript time that turns out to be the then near present when he pictures the poet seeking inspiration from Nature (Stanza 7) while science and medicine forge new paths but lives of citizens deteriorate and the poor pray for redemption from the stable order of the past (Stanza 9) that Auden has already described.
In Stanzas 10 and 11, the people of the nations pray to the "life," the creator (not capitalized by Auden and so being universal rather than of a particular religion) to intervene in the course of the disintegration of human unity and compassion in the world ("But the lives of my friends. I inquire. I inquire.") and appear as a dove (Biblical allusion to John the Baptist's encounter with Jesus), a furious father (Biblical allusion to the Judaic god as a benevolent Father), or an engineer (Biblical allusion to Jesus Christ who came as a new manifestation of God and is expected to return to Earth as a...an engineer...?).
in Stanza 12, 13 and 14, the "life," the creator answers "No," saying that he is already present in what people say, do, choose and desire: today he is Spain, tearing itself asunder in revolt against Fascism. In Stanzas 15 through 19, the people of Spain respond by forming a people's army to fight together as "life." Auden then switches to "To-morrow" in Stanzas 20 through 23.
Tomorrow there may be a future. Tomorrow there may be academic research, romantic love, poets absorbed in their art, bicycle races and suburbs in summer evenings. Then comes a final reference to "To-day" in concluding Stanzas 24 and 25.
Today, along with struggle appended to "To-morrow" in Stanzas 22 and 23, there is death, guilt from the murder done in war, inadequate consolation for loss, friendship cemented before each parts to do the "hurt" of war. In the last stanza, Stanza 26, the stars themselves have died, removing light and hope and aspiration from life; animals stand far off from humankind's actions, refusing to look; mankind is alone. The history that the poet was pleading in Stanzas 1 through 6 "May say Alas but cannot help nor pardon."