Flanders Fields is the generic name of the World War I battlefields in the medieval County of Flanders. At the time of World War I, the county no longer existed but corresponded approximately to the Belgian provinces East Flanders and West Flanders and the French Nord-Pas-de-Calais region. The name is particularly associated with the battles of Ypres, Passchendaele, and the Somme. For most of the war, the front line ran continuously from south of Zeebrugge, Belgium, to the Swiss border with France (Alsace and Vosges regions). Canadian Lieutenant Colonel John McCrae wrote a poem, In Flanders Fields, inspired by his service during the 2nd Battle of Ypres.