Charles's army set up siege lines to the North and West of the city; the South and East were guarded by the rivers Krur and Rhine, respectively. Two large islands lay in the Rhine, however, and Charles decided to capture them, reasoning that he would then control passage along the Rhine (and thus prevent the city from being resupplied) and the water supply to the city's moat. Several assaults in early and mid-August eventually captured the islands, though with heavy losses; soon thereafter a bridge to one of the islands collapsed, drowning many of Charles' Italian soldiers. The Burgundians were also harried by hostile peasants.