 As agreed at Compiègne in 1635, the French replaced Swedish garrisons in Alsace; prior to his death in 1639, Bernard of Saxe-Weimar won a series of victories in the Rhineland, the most important being the capture of Breisach in December 1638.This severed the Spanish Road, forcing Spain to reinforce their armies by sea, where the Dutch had maritime supremacy; in 1639, they destroyed a large supply convoy at the Downs.They also attacked Portuguese possessions in Africa and the Americas, then part of the Spanish Empire; Madrid's inability to prevent this caused increasing unrest in Portugal.