On this date in 1478, a coup d’etat against the Medici family in Florence was attempted during Easter mass — and by day’s end, its leading perpetrators had been hanged.

The Pazzi conspiracy implicates, even more than the municipal political rivalries of the Pazzi and Medici families, the peninsular geopolitics pitting Florence against the Pope, each side with its own constellations of allied lords and city-states.

The arrangement of players and their assorted interests is amply covered elsewhere; we shall suffice for this space to say that the Pazzi were a family of wealth and lineage (another death-sentenced Florentine, Dante, had dropped a couple of their ancestors into his infernal tableau), and proceed to the aftermath.

When one strikes a king, one must strike to kill. In this case, the co-ruling Medici brothers, Giuliano and Lorenzo were both attacked — but Lorenzo survived, and visited a terrible vengeance upon the assailants.

An enraged mob — the Pazzi had misjudged the city’s mood to begin with, and committing murder in church was ill-calculated to win sympathy — and a star chamber of Medici loyalists immediately began rounding up the numerous conspirators, many of whom were summarily hanged from the windows of the Palazzo Vecchio.

Along with a number of obscure foot soldiers and family retainers who suffered such indignities as being thrown from high windows onto cobblestones and torn apart by the mob, the most prominent victims this day were Francesco de Pazzi (the link is to his Italian wikipedia page) and Archbishop Francesco Salviati, a papal loyalist whose grievance against Florence for delaying his seat as archbishop of Pisa had done much to instigate the conspiracy.

They were far from the only victims: fugitives who had escaped the city were hunted for weeks and months thereafter, although Lorenzo “the Great” — who cuts the very model of the enlightened prince to posterity, rightly or not — was disposed in several cases to grant mercy to innocents against the dictates of political expediency.

However, the culpable after this day had every reason to fear. Perhaps the most affecting story is that of elderly Pazzi patriarch Jacopo de Pazzi (Italian again), caught in flight by Tuscan villagers whom he tried desperately (and unavailingly) to bribe for the privilege of suicide rather than a return to the fate of his kinsmen. Florentine communal pride celebrated popular participation in vengeance against the papal plot. Botticelli was commissioned to paint the executed conspirators hanging in their death throes on the very facade of the palace where they had in fact been put to death.

The Pazzi family wasn’t quite blotted out literally — later, it would even be restored to the city — but a comprehensive sentence of civic damnatio memoriae followed in the weeks after the immediate danger was checked. The family property was confiscated, its name and coat of arms banished, even the public festival its Crusader forebear had inspired was (unsuccessfully) renamed. For a time, merely to marry a Pazzi was to exclude oneself from public office.

Niccolo Machiavelli was a boy of eight at the time the Pazzi conspiracy was attempted. As a political theorist in later years, the event would liberally illustrate his writings. In Machiavelli’s Discourses (available free from Project Gutenberg), for instance, the Pazzi conspiracy is a lesson in the danger of conspiring against two princes at once, the risk inherent in having any great number of people aware of the plot, and the unpredictable small turns of fortune and minor slips in execution upon which a great matter may succeed or fail.

[I]n these grave undertakings, no one who is without such experience, however bold and resolute, is to be trusted.

The confusion of which I speak may either cause you to drop your weapon from your hand, or to use words which will have the same results. Quintianus being commanded by Lucilla, sister of Commodus, to slay him, lay in wait for him at the entrance of the amphitheatre, and rushing upon him with a drawn dagger, cried out, “The senate sends you this;” which words caused him to be seized before his blow descended. In like manner Messer Antonio of Volterra, who as we have elsewhere seen was told off to kill Lorenzo de’ Medici, exclaimed as he approached him, “Ah traitor!” and this exclamation proved the salvation of Lorenzo and the ruin of that conspiracy.

Machiavelli also renders his account of this day’s affair in his History of Florence, another Gutenberg freebie.

A detailed exploration of the event is available here.

On this day..

• 3rd Century BCE: Grauballe Man
• 1831: Atanasio, shot for some buttons
• 1916: Francis Sheehy-Skeffington, Patrick McIntyre and Thomas Dickson, by Captain Bowen-Colthurst
• 1947: Hisao Tani, for the rape of Nanking
• 1875: William Hole, family tragedy
• Feast Day of Popes Cletus and Marcellinus
• 1784: Angelo Duca, primitive rebel
• 1926: Shao Piaoping, journalist
• 1945: Sigmund Rascher, feared science
• 1843: Ewen Cameron, black bean leftover
• 1901: "Black Jack" Tom Ketchum, who was left in three pieces
• 1861: Paula Angel ... but why?