On 28 December 1478, in the narrow, snowbound Leventina valley below the Gotthard Pass, a small force of Swiss soldiers and local men from the valley ambushed an army of the Duchy of Milan near the village of Giornico and put it to flight. In Ticino it is remembered as the battaglia dei Sassi Grossi, the Battle of the Big Stones, for the boulders and tree trunks the defenders sent down on the Milanese column. The victory kept the Leventina under the Swiss canton of Uri. The date is in the Julian calendar, then used throughout Europe.
A valley between Milan and Uri
The Leventina, the upper valley of the Ticino river, controlled the southern approach to the Gotthard Pass, and for more than a century the Duchy of Milan and the Swiss cantons fought over it. In 1466 it had been awarded to the canton of Uri, but Milan refused to hand it over, and the quarrel was sharpened when the duchy sided with Charles the Bold of Burgundy, then at war with the Swiss.1
In November 1478 the men of Uri crossed the Gotthard and marched into the Leventina, where the people of the valley, long hostile to Milan, welcomed them as liberators and joined them. Other Swiss cantons sent troops, and on 30 November the Confederate army camped before the walls of Bellinzona. The fortress held out against a siege of about two weeks, and with heavy snow making supply difficult the Swiss withdrew back over the pass.2
The ambush in the snow
Milan sent an army to punish the valley and push on toward the Gotthard. It reached the Magadino plain on 16 December. The Historical Dictionary of Switzerland puts it at 10,000 men, while the Swiss broadcaster RSI gives 8,000. Only a rear guard of 175 Confederate soldiers had stayed behind, reinforced by about 400 men of the Leventina, and they took up position near Giornico.3
On 28 December they struck the Milanese column as it advanced in the narrow, snow-filled valley. RSI describes how the Leventines used surprise, their knowledge of the ground and their skill in moving over the snow, and rolled tree trunks and boulders onto the enemy, throwing the column into a chaos where it could not maneuver. The Historical Dictionary of Switzerland says only that the small force put the much larger army to flight by a stratagem.4
Losses and peace
RSI puts the Milanese losses at more than a thousand men, against 50 Leventines killed and more than 60 wounded, with the Confederates, who stood farther back, reporting only 12 wounded by firearms. A martyrology written in the parish of Quinto in the valley recorded the battle each year on the feast of the Holy Innocents, and the victors built a small church dedicated to the Holy Innocents at Pollegio, near the mass graves.5
After the defeat Milan gave up its claim to the Leventina, which returned to Uri, while Bellinzona stayed Milanese. The Historical Dictionary of Switzerland dates the Sforza dukes' final recognition of Uri's rule to a peace of 1480, and the renunciation of the Milan cathedral chapter's rights in the valley to 1487. A monument at Giornico shows a fighter heaving a boulder down on the enemy.6
