Girolamo Savonarola (1452 – 1498), Italian Dominican friar from Ferrara active in Renaissance Florence. Preached and prophesied civic glory for Florence as a New Jerusalem, and the destruction of secular art and culture. Known for public "bonfires of vanities" and calls for Christian renewal. He denounced clerical corruption, despotic rule, and the exploitation of the poor.

In September 1494, Charles VIII of France invaded Italy and threatened Florence, and doomsday prophecies seemed on the verge of fulfilment. Savonarola intervened with the French king, and led the Florentines to expel the ruling Medicis. A "popular" republic was established. Savonarola declared it would be "richer, more powerful, more glorious than ever". He instituted an extreme puritanical campaign and regime, curiously attracting otherwise hopeless Florentine youth and poor.

In 1495 Florence refused to join Pope Alexander VI's Holy League against the French. The Vatican summoned Savonarola to Rome and banned his preaching. He disobeyed, and further defied the pope with public campaigns for reform with processions, bonfires of the vanities, and pious theatricals. In retaliation, the pope excommunicated him and threatened to place Florence under an interdict. A trial by fire proposed by a rival Florentine preacher to test Savonarola's divine mandate turned into a fiasco, because Savonarola refused the test. Popular opinion turned against him. Savonarola and two of his supporting friars were imprisoned. While in prison, Savonarola continued preaching, and wrote homilies, including these on the text of Psalms 31 and 51. On 23 May 1498, Church and civil authorities condemned, hanged, and burned the three friars in the main square of Florence.

According to Wikipedia, "Savonarola's devotees, the Piagnoni, kept his cause of republican freedom and religious reform alive well into the following century, although the Medici—restored to power in 1512 with the help of the papacy—eventually broke the movement. Some Protestants, including Martin Luther himself, consider Savonarola to be a vital precursor to the Reformation."

Psalm 31 and 51 are both less than a page in length, and the homilies are relatively lengthy. This work runs to 142 pages, including Introduction.