The Somme ( , , ) is a river in Picardy, northern France. The river is in length, from its source in the high ground of the former at Fonsomme near Saint-Quentin, to the Bay of the Somme, in the English Channel. It lies in the geological syncline which also forms the Solent. This gives it a fairly constant and gentle gradient where several fluvial terraces have been identified. Name The Somme river was known in ancient times as Samara. It presumably means 'the summery river', that is to say the 'quiet river', stemming from an adjective *sam-aro- ('summery') itself derived from the Celtic root *samo- ('summer'). The city of Amiens was also known as Samarobriva (Gaulish: 'bridge on the Samara'). It is attested by the early 1st century BC as the chief town of the Ambiani, an ancient Gallic tribe of the region. The modern department of Somme was named after this river. History The Somme has featured prominently in several military campaigns. In 1066, the invasion fleet of William the Conqueror assembled in the Bay of the Somme, at Saint-Valery-sur-Somme. The river also featured in the 1346 withdrawal of Edward III of England's army, which forded the river at the Battle of Blanchetaque during the campaign, which culminated in the Battle of Crécy. Crossing the river also featured prominently in the campaign which led to the Battle of Agincourt in 1415. In 1636, a Spanish army led by Thomas Francis, Prince of Carignano, crossed the Somme defeating a French army during the Thirty Years War threatening Paris. Most famously, the Battle of the Somme, during World War I, lasted from July to November 1916 and resulted in more than a million casualties. Private A. S. Bullock in his wartime memoir recalled his first sight of it in early April 1918: "... we reached a small place called Hengest sur Somme. The train stopped and we descended. There in front of us was a muddy, sluggish and somewhat narrow stream, which has given its name to one of the most awful battles in history – the Somme." The great battles that finally stopped the German advance in the Spring Offensive of 1918 were fought around the valley of the Somme in places like Villers Bretonneux, which marked the beginning of the end of the war. Départements and towns along the river Aisne: Saint-Quentin Somme : Ham, Péronne, Corbie, Amiens,