The charms of Twitter wear thin quickly, but here’s one good use for that medium: asking your friendly neighborhood historian about one of their favorite topics.
Great question, Joshua! (Sorry it took two weeks to answer it.) In fact, it had been in the back of my mind since our January travel course on WWI, when our Belgian tour guide mentioned in passing that “Western front” is “what the Germans called it.” After all, the sites we visited in Flanders and Picardy are to the west of a central European power that was also fighting a massive campaign on its eastern front against Russia.
(Actually, the first use of “Western front” that I can find in BYU’s extensive World War I Document Archive, while from a German source, has to do with an entirely different theater of the war. On July 29, 1914, a memo from the German general staff to that country’s Foreign Office analyzed the situation on “der serbischen Westfront” — that is, on the border of the Austro-Hungarian Empire, where the war started several days before German forces entered Belgium en route to Paris.)
As distinguishing the two halves of Germany’s war, “western front” shows up in English-language newspaper accounts almost from the start of the war. Three days after Britain joined the war, The Sheffield Independent reported that “The belief here is growing that Germany has put her entire force upon the Western front, in which case Russia will hardly content to await the attack to suit the German programme.” (That’s the first mention of “Western front” that turns up in the British Newspaper Archive.) “British Forces in Battle Along the Entire Western Front,” announced the front page of a Welsh newspaper on August 25th. Two weeks later, as French and British troops defended Paris along the Marne, an Associated Press report from Berlin summed up the situation: “A series of gigantic battles along the western front, from Brussels to the Swiss frontier, has been fought….”
So it seems that “the Western front” was in usage right from the start. But it’s not quite so clear how widely it was used. The earliest reference that I can find in the BYU archive is a March 10, 1915 report on the Battle of Neuve Chapelle (a semi-successful British attack in Artois) by Charles de Souza. But when he wrote the four-volume Germany in Defeat: A Strategic History of the War, de Souza didn’t use the phrase “Western front” until near the end of the second book, published in 1917. (The first, from 1916, alludes a couple of times to “the western theatre of the war.”)
Similarly, in 1917 a posthumous war memoir called A Student in Arms was published, with a note explaining that the author, “Mr. Donald Hankey was killed in action on the Western Front on October 26, 1916.” But Hankey himself didn’t use that phrase a single time in chapters that were originally published anonymously in The Spectator in 1915-1916.