On the Late Massacre in Piedmont
History and Background 
In 1487, shortly after the Crusades in Southern France, Pope Innocent VIII turned his focus to the Waldensians in Northern Italy. The group was excommunicated from the church after refusing to conform to Catholicism. The Church gave them twenty days to sell their lands and leave the town or to attend Catholic mass. When he found out that many of the townspeople had fled, he created a false uprising to send in troops. As part of the ordinance he required the townspeople to shelter the troops in their homes. The quartering order was not required, but was a way to get the troops close to the people without raising suspicion. On April 24, 1655 there was an order given to begin the attack on the people. It is said that the Catholic forces went beyond reason of attacking the Waldensians. They are reported to have unleashed an unprovoked campaign of looting, rape, torture, and murder. The estimated number of people killed was around 2,000 people killed and another 2,000 reformed to the Catholic faith. Word of the killings spread quickly throughout Europe and great efforts were made to remove any survivors from the area and bring them to safety. This events of this massacre are what lead to inspiration and writing of John Milton’s sonnet “On the Late Massacre in Piedmont.”
Form and Style 
Milton’s Sonnet 18 is a sonnet with an iambic pentameter rhythm scheme with ten syllables per line consisting of 14 lines. Milton's sonnet does not follow the Shakespearean sonnet form, however; it does have three quatrains and finishes with a couplet, this sonnet follows ABBA, ABBA, CDCDCD rhyme scheme. In the third quatrain this changes and the poem reveals who is behind the massacre: the “Triple Tyrant," a reference to Pope Innocent III.
Themes and Motifs 
The largest theme of the sonnet is religion, though calling on religion to enact justice. The other theme is the movement from Old Testament to the New Testament. The poem compares the theme of vengeance from the Old Testament to the theme of regeneration in the New Testament. The clear example of vengeance in the poem is the first line of “Avenge, O Lord,” which could be a reference to Luke 18:7, a bible verse that speaks about vengeance. An example of regeneration is the lines “grow/ A hundredfold” and “Mother with Infant.”
David Elsensohn writes on God's wrath in the context of the poem. Elsensohn disagrees with Milton that God's wrath should be called down; rather, Elsensohn argues for understanding:
"Milton's outrage mirrors my own doubts and disdain for overly zealous adherence to dogma and the elevation of Scripture to near-divine status; cleaving too tightly to power and one's own view of divinity leads never to enlightenment or to peace, but to violence and oppression. While Milton calls for the Lord's own wrath to expose and avenge the wrongdoing, I call for acceptance of all faiths and of no faith. Such acts must always be told - their cries echoing over the hills, and to Heaven - for only by exposure and universal condemnation are such acts of hatred lessened and eventually ceased."