French Intervention in Valtellina (1620s)

Timeline

1. 1620–1622Valtellina valley · LombardyValtellina controlled key Alpine passages linking Spanish Milan to Habsburg Austria; in 1620 local Catholic 'mobs' massacred Protestants, pitting the Grisons against the Habsburg camp, and France saw an opportunity to weaken Spain's southern flank and secure links with Switzerland.
2. 1624–1625Northern foothills of the Alps · AlpsAfter Richelieu entered the council in 1624, southern-flank planning accelerated; in 1625 French forces advanced through Switzerland toward Valtellina, seeking to restore Grisons control of the valley and prevent the Spanish Habsburgs from monopolizing the passes.
3. 1626Splügen Pass · GraubündenIn 1626 French and Grisons allied forces defeated Spanish-backed Catholic local militias near the Splügen Pass, briefly establishing French influence over the Alpine corridor but failing to hold all of Valtellina long-term.
4. 1627–1630Valtellina and Milan · ItalyAfter 1627, French domestic and military pressures such as the Siege of La Rochelle limited sustained large-scale southern-flank operations; between 1629 and 1630 France and Spain reached a diplomatic stalemate over Valtellina, and military intervention became intermittent.