
Above is a photo of a Romanian Maxim machine gun on a horse drawn carriage, during the early part of World War 1. Machine Guns of this type were not much different from the maxim guns that had been first introduced in 1884 and therefore represented military technology that was nearly 30 years old. . Although they could lay down a relatively heavy fire (about 500 rounds per minute), they were large and cumbersome and needed to be dragged by horses. Also their size made it difficult if not impossible to use the terrain to protect the firing crew so that they were mostly used in open fields where they were effective against exposed infantry, but also were very vulnerable to enemy counter fire.
When Hiram Maxim invented his machine gun in the 1800s, its usefulness was immediately recognized by the United States and the European powers, who rushed to add it to their arsenals. The gun was revolutionary because it greatly increased the rate of fire that a few soldiers could put out. With this gun, a single gun crew could equal the firepower of an entire platoon or more of soldiers. However by the start of World War 1, the maxim gun was yesterday’s technology and both sides had invented much better tools for killing.
Nevertheless the maxim machine gun was still a common sight on the battlefields of Europe during World War 1.

Both sides including France and Germany had a number of these fairly obsolete machine guns in their arsenals at the start of the war. The major powers quickly equipped their soldiers with lighter and more mobile machine guns, which not only had a higher rate of fire but also a lower silhouette so that the machine gun crew stood a better chance of survival and could move their gun into a new position themselves rather than having to hitch it to a horse.
Despite the eventual obsolescence of the maxim machine gun, it continued to see service on the fringes of empire, in the colonies during World War 1, and during the Russian Revolution, as well as in the proxy wars in China and elsewhere, well into the 20th century. Some Maxim guns were still in use in WW2.
A famous propaganda poster from the Russian Revolution credits Lenin with heroically manning a maxim machine gun mounted on on a horse drawn cart, firing while being pursued by counter revolutionary White Russian forces.