Much of the fighting took place around the Spanish Road, an overland supply route connecting Spanish possessions in Northern Italy to Flanders. Rarely used for moving soldiers post-1601, it remained vital for trade, and went through areas like Alsace essential to French security. In Northern Italy, Savoy and the Spanish-held Duchy of Milan were strategically important, since they provided access to the vulnerable southern borders of France, and Habsburg territories in Austria. Richelieu aimed to end Spanish dominance in these areas, an objective largely achieved by the time he died in 1642.