In July 1346, Edward mounted a major invasion across the channel, landing in Normandy's Cotentin, at St. Vaast. The English army captured the city of Caen in just one day, surprising the French. Philip mustered a large army to oppose Edward, who chose to march northward toward the Low Countries, pillaging as he went. He reached the river Seine to find most of the crossings destroyed. He moved further and further south, worryingly close to Paris, until he found the crossing at Poissy. This had only been partially destroyed, so the carpenters within his army were able to fix it. He then continued on his way to Flanders until he reached the river Somme. The army crossed at a tidal ford at Blanchetaque, leaving Philip's army stranded. Edward, assisted by this head start, continued on his way to Flanders once more, until, finding himself unable to outmanoeuvre Philip, Edward positioned his forces for battle and Philip's army attacked.